-_dnl__ -*-Texinfo-*-
+_dnl__ -*-Texinfo-*-
_dnl__ Copyright (c) 1988 1989 1990 1991 Free Software Foundation, Inc.
-\input texinfo
+_dnl__ $Id$
+\input texinfo @c -*-texinfo-*-
+@c Copyright (c) 1988 1989 1990 1991 Free Software Foundation, Inc.
+@c %**start of header
@setfilename _GDBP__.info
-@c $Id$
+_if__(_GENERIC__)
+@settitle Using _GDBN__ (<v>_GDB_VN__)
+_fi__(_GENERIC__)
+_if__(!_GENERIC__)
+@settitle Using _GDBN__ <v>_GDB_VN__ (_HOST__)
+_fi__(!_GENERIC__)
+@setchapternewpage odd
+@c @smallbook
+@c @cropmarks
+@c %**end of header
+
+@finalout
+@syncodeindex ky cp
+
+_0__@c ===> NOTE! <==_1__
+@c Determine the edition number in *three* places by hand:
+@c 1. First ifinfo section 2. title page 3. top node
+@c To find the locations, search for !!set
+
+@c The following is for Pesch for his RCS system.
+@c This revision number *not* the same as the Edition number.
+@tex
+\def\$#1${{#1}} % Kluge: collect RCS revision info without $...$
+\xdef\manvers{\$Revision$} % For use in headers, footers too
+@end tex
+
+@c FOR UPDATES LEADING TO THIS DRAFT, GDB CHANGELOG CONSULTED BETWEEN:
+@c Fri Oct 11 23:27:06 1991 John Gilmore (gnu at cygnus.com)
+@c Sat Dec 22 02:51:40 1990 John Gilmore (gnu at cygint)
+
@c THIS MANUAL REQUIRES TEXINFO-2 macros and info-makers to format properly.
-@c
-@c NOTE: this manual is marked up for preprocessing with a collection
-@c of m4 macros called "pretex.m4". If you see <_if__> and <_fi__>
-@c scattered around the source, you have the full source before
-@c preprocessing; if you don't, you have the source configured for
-@c _HOST__ architectures (and you can of course get the full source,
-@c with all configurations, from wherever you got this).
+
+@ifinfo
+@format
+START-INFO-DIR-ENTRY
+* Gdb: (gdb). The GNU debugger.
+END-INFO-DIR-ENTRY
+@end format
+@end ifinfo
_if__(0)
+NOTE: this manual is marked up for preprocessing with a collection
+of m4 macros called "pretex.m4".
+
THIS IS THE SOURCE PRIOR TO PREPROCESSING. The full source needs to
be run through m4 before either tex- or info- formatting: for example,
_0__
- m4 pretex.m4 none.m4 m680x0.m4 gdb.texinfo >gdb-680x0.texinfo
-_1__
+ m4 pretex.m4 none.m4 all.m4 gdb.texinfo >gdb-all.texinfo
will produce (assuming your path finds either GNU m4 >= 0.84, or SysV
m4; Berkeley won't do) a file suitable for formatting. See the text in
"pretex.m4" for a fuller explanation (and the macro definitions).
+_1__
_fi__(0)
-@tex
-\def\$#1${{#1}} % Kluge: collect RCS revision info without $...$
-\xdef\manvers{\$Revision$} % For use in headers, footers too
-@end tex
@c
-@syncodeindex ky cp
-@c FOR UPDATES LEADING TO THIS DRAFT, GDB CHANGELOG CONSULTED BETWEEN:
-@c Wed Jul 31 12:06:29 1991 John Gilmore (gnu at cygint.cygnus.com)
-@c Sat Dec 22 02:51:40 1990 John Gilmore (gnu at cygint)
@ifinfo
This file documents the GNU debugger _GDBN__.
+@c !!set edition, date, version
+This is Edition 4.00, December 1991,
+of @cite{Using GDB: A Guide to the GNU Source-Level Debugger}
+for GDB Version _GDB_VN__.
+
Copyright (C) 1988, 1989, 1990, 1991 Free Software Foundation, Inc.
Permission is granted to make and distribute verbatim copies of
included in a translation approved by the Free Software Foundation
instead of in the original English.
@end ifinfo
-@smallbook
-@setchapternewpage odd
-_if__(_GENERIC__)
-@settitle Using _GDBN__ (v4.0)
-_fi__(_GENERIC__)
-_if__(!_GENERIC__)
-@settitle Using _GDBN__ v4.0 (_HOST__)
-_fi__(!_GENERIC__)
-@iftex
-@finalout
-@end iftex
@titlepage
-@title{Using _GDBN__}
-@subtitle{A Guide to the GNU Source-Level Debugger}
+@title Using _GDBN__
+@subtitle A Guide to the GNU Source-Level Debugger
_if__(!_GENERIC__)
-@subtitle{On _HOST__ Systems}
+@subtitle On _HOST__ Systems
_fi__(!_GENERIC__)
@sp 1
-@c Maybe crank this up to "Fourth Edition" when released at FSF
-@c @subtitle Third Edition---_GDBN__ version 4.0
-@subtitle _GDBN__ version 4.0
-@subtitle July 1991
-@author{Richard M. Stallman@qquad @hfill Free Software Foundation}
-@author{Roland H. Pesch@qquad @hfill Cygnus Support}
+@c !!set edition, date, version
+@subtitle Edition 4.00, for _GDBN__ version _GDB_VN__
+@subtitle December 1991
+@author by Richard M. Stallman and Roland H. Pesch
@page
@tex
{\parskip=0pt
@end titlepage
@page
-@node Top, Summary, (dir), (dir)
@ifinfo
-This file describes version 4.0 of GDB, the GNU symbolic debugger.
+@node Top, Summary, (dir), (dir)
+@top _GDBN__, the GNU symbolic debugger
+
+This file describes _GDBN__, the GNU symbolic debugger.
+
+@c !!set edition, date, version
+This is Edition 4.00, December 1991, for GDB Version _GDB_VN__.
@end ifinfo
@menu
-* Summary:: Summary of _GDBN__
-* New Features:: New Features in _GDBN__ version 4.0
-* Sample Session:: A Sample _GDBN__ Session
-* Invocation:: Getting In and Out of _GDBN__
-* Commands::
-* Running:: Running Programs Under _GDBN__
-* Stopping:: Stopping and Continuing
-* Stack:: Examining the Stack
-* Source:: Examining Source Files
-* Data:: Examining Data
-* Symbols:: Examining the Symbol Table
-* Altering:: Altering Execution
-* _GDBN__ Files::
-* Targets:: Specifying a Debugging Target
-* Controlling _GDBN__:: Controlling _GDBN__
-* Sequences:: Canned Sequences of Commands
-* Emacs:: Using _GDBN__ under GNU Emacs
-* _GDBN__ Bugs:: Reporting Bugs in _GDBN__
-* Renamed Commands::
-* Installing _GDBN__:: Installing _GDBN__
-* Copying:: GNU GENERAL PUBLIC LICENSE
-* Index:: Index
+* Summary:: Summary of _GDBN__
+* New Features:: New features since _GDBN__ version 3.5
+* Sample Session:: A sample _GDBN__ session
+* Invocation:: Getting in and out of _GDBN__
+* Commands:: _GDBN__ commands
+* Running:: Running programs under _GDBN__
+* Stopping:: Stopping and continuing
+* Stack:: Examining the stack
+* Source:: Examining source files
+* Data:: Examining data
+* Languages:: Using _GDBN__ with different languages
+* Symbols:: Examining the symbol table
+* Altering:: Altering execution
+* _GDBN__ Files:: _GDBN__'s files
+* Targets:: Specifying a debugging target
+* Controlling _GDBN__:: Controlling _GDBN__
+* Sequences:: Canned sequences of commands
+* Emacs:: Using _GDBN__ under GNU Emacs
+* _GDBN__ Bugs:: Reporting bugs in _GDBN__
+* Renamed Commands::
+* Installing _GDBN__:: Installing _GDBN__
+* Copying:: GNU GENERAL PUBLIC LICENSE
+* Index:: Index
+
--- The Detailed Node Listing ---
Summary of _GDBN__
-* Free Software:: Free Software
-* Contributors:: Contributors to _GDBN__
+* Free Software:: Free Software
+* Contributors:: Contributors to _GDBN__
Getting In and Out of _GDBN__
-* Starting _GDBN__:: Starting _GDBN__
-* Leaving _GDBN__:: Leaving _GDBN__
-* Shell Commands:: Shell Commands
+* Invoking _GDBN__:: Starting _GDBN__
+* Leaving _GDBN__:: Leaving _GDBN__
+* Shell Commands:: Shell Commands
Starting _GDBN__
-* File Options:: Choosing Files
-* Mode Options:: Choosing Modes
+* File Options:: Choosing Files
+* Mode Options:: Choosing Modes
_GDBN__ Commands
-* Command Syntax:: Command Syntax
-* Help:: Getting Help
+* Command Syntax:: Command Syntax
+* Help:: Getting Help
Running Programs Under _GDBN__
-* Compilation:: Compiling for Debugging
-* Starting:: Starting your Program
-* Arguments:: Your Program's Arguments
-* Environment:: Your Program's Environment
-* Working Directory:: Your Program's Working Directory
-* Input/Output:: Your Program's Input and Output
-* Attach:: Debugging an Already-Running Process
-* Kill Process:: Killing the Child Process
+* Compilation:: Compiling for Debugging
+* Starting:: Starting your Program
+* Arguments:: Your Program's Arguments
+* Environment:: Your Program's Environment
+* Working Directory:: Your Program's Working Directory
+* Input/Output:: Your Program's Input and Output
+* Attach:: Debugging an Already-Running Process
+* Kill Process:: Killing the Child Process
Stopping and Continuing
-* Breakpoints:: Breakpoints, Watchpoints, and Exceptions
-* Continuing and Stepping:: Resuming Execution
-* Signals:: Signals
+* Breakpoints:: Breakpoints, Watchpoints, and Exceptions
+* Continuing and Stepping:: Resuming Execution
+* Signals:: Signals
Breakpoints, Watchpoints, and Exceptions
-* Set Breaks:: Setting Breakpoints
-* Set Watchpoints:: Setting Watchpoints
-* Exception Handling:: Breakpoints and Exceptions
-* Delete Breaks:: Deleting Breakpoints
-* Disabling:: Disabling Breakpoints
-* Conditions:: Break Conditions
-* Break Commands:: Breakpoint Command Lists
-* Breakpoint Menus:: Breakpoint Menus
-* Error in Breakpoints::
+* Set Breaks:: Setting Breakpoints
+* Set Watchpoints:: Setting Watchpoints
+* Exception Handling:: Breakpoints and Exceptions
+* Delete Breaks:: Deleting Breakpoints
+* Disabling:: Disabling Breakpoints
+* Conditions:: Break Conditions
+* Break Commands:: Breakpoint Command Lists
+* Breakpoint Menus:: Breakpoint Menus
+* Error in Breakpoints:: ``Cannot insert breakpoints''
Examining the Stack
-* Frames:: Stack Frames
-* Backtrace:: Backtraces
-* Selection:: Selecting a Frame
-* Frame Info:: Information on a Frame
+* Frames:: Stack Frames
+* Backtrace:: Backtraces
+* Selection:: Selecting a Frame
+* Frame Info:: Information on a Frame
Examining Source Files
-* List:: Printing Source Lines
-* Search:: Searching Source Files
-* Source Path:: Specifying Source Directories
-* Machine Code:: Source and Machine Code
+* List:: Printing Source Lines
+* Search:: Searching Source Files
+* Source Path:: Specifying Source Directories
+* Machine Code:: Source and Machine Code
Examining Data
-* Expressions:: Expressions
-* Variables:: Program Variables
-* Arrays:: Artificial Arrays
-* Output formats:: Output formats
-* Memory:: Examining Memory
-* Auto Display:: Automatic Display
-* Print Settings:: Print Settings
-* Value History:: Value History
-* Convenience Vars:: Convenience Variables
-* Registers:: Registers
-* Floating Point Hardware:: Floating Point Hardware
+* Expressions:: Expressions
+* Variables:: Program Variables
+* Arrays:: Artificial Arrays
+* Output formats:: Output formats
+* Memory:: Examining Memory
+* Auto Display:: Automatic Display
+* Print Settings:: Print Settings
+* Value History:: Value History
+* Convenience Vars:: Convenience Variables
+* Registers:: Registers
+* Floating Point Hardware:: Floating Point Hardware
+
+Using GDB with Different Languages
+
+* Setting:: Switching between source languages
+* Show:: Displaying the language
+* Checks:: Type and Range checks
+* Support:: Supported languages
+
+Switching between source languages
+
+* Manually:: Setting the working language manually
+* Automatically:: Having GDB infer the source language
+
+Type and range Checking
+
+* Type Checking:: An overview of type checking
+* Range Checking:: An overview of range checking
+
+Supported Languages
+
+* C:: C and C++
+* Modula-2:: Modula-2
+
+C and C++
+
+* C Operators:: C and C++ Operators
+* C Constants:: C and C++ Constants
+* Cplusplus expressions:: C++ Expressions
+* C Defaults:: Default settings for C and C++
+* C Checks:: C and C++ Type and Range Checks
+* Debugging C:: _GDBN__ and C
+* Debugging C plus plus:: Special features for C++
+
+Modula-2
+
+* M2 Operators:: Built-in operators
+* Built-In Func/Proc:: Built-in Functions and Procedures
+* M2 Constants:: Modula-2 Constants
+* M2 Defaults:: Default settings for Modula-2
+* Deviations:: Deviations from standard Modula-2
+* M2 Checks:: Modula-2 Type and Range Checks
+* M2 Scope:: The scope operators @code{::} and @code{.}
+* GDB/M2:: GDB and Modula-2
Altering Execution
-* Assignment:: Assignment to Variables
-* Jumping:: Continuing at a Different Address
-* Signaling:: Giving the Program a Signal
-* Returning:: Returning from a Function
-* Calling:: Calling your Program's Functions
+* Assignment:: Assignment to Variables
+* Jumping:: Continuing at a Different Address
+* Signaling:: Giving your program a Signal
+* Returning:: Returning from a Function
+* Calling:: Calling your Program's Functions
+* Patching:: Patching your Program
_GDBN__'s Files
-* Files:: Commands to Specify Files
-* Symbol Errors:: Errors Reading Symbol Files
+* Files:: Commands to Specify Files
+* Symbol Errors:: Errors Reading Symbol Files
-Specifying a Debugging Target
+Specifying a Debugging Target
-* Active Targets:: Active Targets
-* Target Commands:: Commands for Managing Targets
-* Remote:: Remote Debugging
+* Active Targets:: Active Targets
+* Target Commands:: Commands for Managing Targets
+* Remote:: Remote Debugging
Remote Debugging
-* i960-Nindy Remote::
-* EB29K Remote::
-* VxWorks Remote::
+* i960-Nindy Remote:: _GDBN__ with a Remote i960 (Nindy)
+* EB29K Remote:: _GDBN__ with a Remote EB29K
+* VxWorks Remote:: _GDBN__ and VxWorks
_GDBN__ with a Remote i960 (Nindy)
-* Nindy Startup:: Startup with Nindy
-* Nindy Options:: Options for Nindy
-* Nindy reset:: Nindy Reset Command
+* Nindy Startup:: Startup with Nindy
+* Nindy Options:: Options for Nindy
+* Nindy reset:: Nindy Reset Command
_GDBN__ with a Remote EB29K
-* Comms (EB29K):: Communications Setup
-* gdb-EB29K:: EB29K cross-debugging
-* Remote Log:: Remote Log
+* Comms (EB29K):: Communications Setup
+* gdb-EB29K:: EB29K cross-debugging
+* Remote Log:: Remote Log
_GDBN__ and VxWorks
-* VxWorks connection:: Connecting to VxWorks
-* VxWorks download:: VxWorks Download
-* VxWorks attach:: Running Tasks
+* VxWorks connection:: Connecting to VxWorks
+* VxWorks download:: VxWorks Download
+* VxWorks attach:: Running Tasks
Controlling _GDBN__
-* Prompt:: Prompt
-* Editing:: Command Editing
-* History:: Command History
-* Screen Size:: Screen Size
-* Numbers:: Numbers
-* Messages/Warnings:: Optional Warnings and Messages
+* Prompt:: Prompt
+* Editing:: Command Editing
+* History:: Command History
+* Screen Size:: Screen Size
+* Numbers:: Numbers
+* Messages/Warnings:: Optional Warnings and Messages
Canned Sequences of Commands
-* Define:: User-Defined Commands
-* Command Files:: Command Files
-* Output:: Commands for Controlled Output
+* Define:: User-Defined Commands
+* Command Files:: Command Files
+* Output:: Commands for Controlled Output
Reporting Bugs in _GDBN__
-* Bug Criteria:: Have You Found a Bug?
-* Bug Reporting:: How to Report Bugs
+* Bug Criteria:: Have You Found a Bug?
+* Bug Reporting:: How to Report Bugs
+
+Installing GDB
+
+* Subdirectories:: Configuration subdirectories
+* Config Names:: Specifying names for hosts and targets
+* configure Options:: Summary of options for configure
+* Formatting Documentation:: How to format and print GDB documentation
@end menu
@node Summary, New Features, Top, Top
The purpose of a debugger such as _GDBN__ is to allow you to see what is
going on ``inside'' another program while it executes---or what another
-program was doing at the moment it crashed.
+program was doing at the moment it crashed.@refill
_GDBN__ can do four main kinds of things (plus other things in support of
-these) to help you catch bugs in the act:
+these) to help you catch bugs in the act:@refill
@itemize @bullet
@item
effects of one bug and go on to learn about another.
@end itemize
-_GDBN__ can be used to debug programs written in C and C++. Pascal support
-is being implemented, and Fortran support will be added when a GNU
-Fortran compiler is ready.
+You can use _GDBN__ to debug programs written in C, C++, and Modula-2.
+Fortran support will be added when a GNU Fortran compiler is ready.
@menu
-* Free Software:: Free Software
-* Contributors:: Contributors to GDB
+* Free Software:: Free Software
+* Contributors:: Contributors to GDB
@end menu
@node Free Software, Contributors, Summary, Summary
Free Software Foundation uses the GPL to preserve these freedoms.
Fundamentally, the General Public License is a license which says that
-you have these freedoms and that you can't take these freedoms away
+you have these freedoms and that you cannot take these freedoms away
from anyone else.
-@c FIXME: (passim) go through all xrefs, expanding to use text headings
-For full details, @pxref{Copying}.
+For full details, @pxref{Copying, ,GNU GENERAL PUBLIC LICENSE}.
@node Contributors, , Free Software, Summary
@unnumberedsec Contributors to GDB
@end quotation
So that they may not regard their long labor as thankless, we
-particularly thank those who shepherded GDB through major releases:
-John Gilmore (release 4.0); Jim Kingdon (releases 3.9, 3.5, 3.4, 3.3);
-and Randy Smith (releases 3.2, 3.1, 3.0). As major maintainer of GDB
-for some period, each contributed significantly to the structure,
-stability, and capabilities of the entire debugger.
+particularly thank those who shepherded GDB through major releases: John
+Gilmore (releases _GDB_VN__, 4.2, 4.1, 4.0); Jim Kingdon (releases 3.9,
+3.5, 3.4, 3.3); and Randy Smith (releases 3.2, 3.1, 3.0). As major
+maintainer of GDB for some period, each contributed significantly to the
+structure, stability, and capabilities of the entire debugger.@refill
Richard Stallman, assisted at various times by Pete TerMaat, Chris
Hanson, and Richard Mlynarik, handled releases through 2.8.
Clark wrote the GNU C++ demangler. Early work on C++ was by Peter
TerMaat (who also did much general update work leading to release 3.0).
-GDB 4.0 uses the BFD subroutine library to examine multiple
-object-file formats; BFD was a joint project of V. Gumby
-Henkel-Wallace, Rich Pixley, Steve Chamberlain, and John Gilmore.
+GDB 4 uses the BFD subroutine library to examine multiple object-file
+formats; BFD was a joint project of V. Gumby Henkel-Wallace, Rich
+Pixley, Steve Chamberlain, and John Gilmore.
-David Johnson wrote the original COFF support; Pace Willison did
-the original support for encapsulated COFF.
+David Johnson wrote the original COFF support; Pace Willison did the
+original support for encapsulated COFF.
Adam de Boor and Bradley Davis contributed the ISI Optimum V support.
Per Bothner, Noboyuki Hikichi, and Alessandro Forin contributed MIPS
-support. Jean-Daniel Fekete contributed Sun 386i support. Chris
-Hanson improved the HP9000 support. Noboyuki Hikichi and Tomoyuki
-Hasei contributed Sony/News OS 3 support. David Johnson contributed
-Encore Umax support. Jyrki Kuoppala contributed Altos 3068 support.
-Keith Packard contributed NS32K support. Doug Rabson contributed
-Acorn Risc Machine support. Chris Smith contributed Convex support
-(and Fortran debugging). Jonathan Stone contributed Pyramid support.
-Michael Tiemann contributed SPARC support. Tim Tucker contributed
-support for the Gould NP1 and Gould Powernode. Pace Willison
-contributed Intel 386 support. Jay Vosburgh contributed Symmetry
-support.
-
-Rich Schaefer helped with support of SunOS shared libraries.
+support. Jean-Daniel Fekete contributed Sun 386i support. Chris Hanson
+improved the HP9000 support. Noboyuki Hikichi and Tomoyuki Hasei
+contributed Sony/News OS 3 support. David Johnson contributed Encore
+Umax support. Jyrki Kuoppala contributed Altos 3068 support. Keith
+Packard contributed NS32K support. Doug Rabson contributed Acorn Risc
+Machine support. Chris Smith contributed Convex support (and Fortran
+debugging). Jonathan Stone contributed Pyramid support. Michael
+Tiemann contributed SPARC support. Tim Tucker contributed support for
+the Gould NP1 and Gould Powernode. Pace Willison contributed Intel 386
+support. Jay Vosburgh contributed Symmetry support.
+
+Rich Schaefer and Peter Schauer helped with support of SunOS shared
+libraries.
Jay Fenlason and Roland McGrath ensured that GDB and GAS agree about
several machine instruction sets.
-Patrick Duval, Ted Goldstein, Vikram Koka and Glenn Engel helped
-develop remote debugging. Intel Corporation and Wind River Systems
-contributed remote debugging modules for their products.
+Patrick Duval, Ted Goldstein, Vikram Koka and Glenn Engel helped develop
+remote debugging. Intel Corporation and Wind River Systems contributed
+remote debugging modules for their products.
-Brian Fox is the author of the readline libraries providing
-command-line editing and command history.
+Brian Fox is the author of the readline libraries providing command-line
+editing and command history.
+
+Andrew Beers of SUNY Buffalo wrote the language-switching code and the
+Modula-2 support, and contributed the Languages chapter of this manual.
@node New Features, Sample Session, Summary, Top
@unnumbered New Features since _GDBN__ version 3.5
@item Targets
Using the new command @code{target}, you can select at runtime whether
you are debugging local files, local processes, standalone systems over
-a serial port, realtime systems over a TCP/IP connection, etc.
-Internally, _GDBN__ now uses a function vector to mediate access to
-different targets; if you need to add your own support for a remote
-protocol, this makes it much easier.
+a serial port, realtime systems over a TCP/IP connection, etc. The
+command @code{load} can download programs into a remote system. Serial
+stubs are available for Motorola 680x0 and Intel 80386 remote systems;
+_GDBN__ also supports debugging realtime processes running under
+VxWorks, using SunRPC Remote Procedure Calls over TCP/IP to talk to a
+debugger stub on the target system. Internally, _GDBN__ now uses a
+function vector to mediate access to different targets; if you need to
+add your own support for a remote protocol, this makes it much easier.
@item Watchpoints
_GDBN__ now sports watchpoints as well as breakpoints. You can use a
changes, without having to predict a particular place in your program
where this may happen.
+@item Wide Output
+Commands that issue wide output now insert newlines at places designed
+to make the output more readable.
+
@item Object Code Formats
-_GDBN__ uses a new scheme called the Binary File Descriptor (BFD)
+_GDBN__ uses a new library called the Binary File Descriptor (BFD)
Library to permit it to switch dynamically, without reconfiguration or
recompilation, between different object-file formats. Formats currently
supported are COFF, a.out, and the Intel 960 b.out; files may be read as
subroutine library so that other programs may take advantage of it, and
the other GNU binary utilities are being converted to use it.
-@item Configuration
+@item Configuration and Ports
Compile-time configuration (to select a particular architecture and
operating system) is much easier. The script @code{configure} now
allows you to configure _GDBN__ as either a native debugger or a
-cross-debugger.
+cross-debugger. @xref{Installing _GDBN__}, for details on how to
+configure and on what architectures are now available.
@item Interaction
The user interface to _GDBN__'s control variables has been simplified
displaying only source language information.
-@item Source Language
-_GDBN__ now has limited support for C++ exception handling: _GDBN__ can
-break when an exception is raised, before the stack is peeled back to
-the exception handler's context.
+@item C++
+_GDBN__ now supports C++ multiple inheritance (if used with a GCC
+version 2 compiler), and also has limited support for C++ exception
+handling, with the commands @code{catch} and @code{info catch}: _GDBN__
+can break when an exception is raised, before the stack is peeled back
+to the exception handler's context.
+
+@item Modula-2
+_GDBN__ now has preliminary support for the GNU Modula-2 compiler,
+currently under development at the State University of New York at
+Buffalo. Coordinated development of both _GDBN__ and the GNU Modula-2
+compiler will continue through the fall of 1991 and into 1992. Other
+Modula-2 compilers are currently not supported, and attempting to debug
+programs compiled with them will likely result in an error as the symbol
+table of the executable is read in.
@item Command Rationalization
Many _GDBN__ commands have been renamed to make them easier to remember
of your program, and the latter refer to the state of _GDBN__ itself.
@xref{Renamed Commands}, for details on what commands were renamed.
-@item Ports
-_GDBN__ has been ported to the following new architectures: AT&T 3b1,
-Acorn RISC machine, HP300 running HPUX, big- and little-endian MIPS
-machines, Motorola 88k, Sun 386i, and Sun 3 running SunOS 4. In
-addition, the following are supported as targets only: AMD 29k, Intel
-960, and Wind River's VxWorks.
-
@item Shared Libraries
-_GDBN__ 4.0 supports SunOS shared libraries.
+_GDBN__ 4 can debug programs and core files that use SunOS shared
+libraries.
+
+@item Reference Card
+_GDBN__ 4 has a reference card; @xref{Formatting Documentation} for
+instructions on printing it.
@item Work in Progress
Kernel debugging for BSD and Mach systems; Tahoe and HPPA architecture
quote strings from the default, the commands used to capture one macro's
definition in another stop working. In the following short @code{m4}
session, we define a macro @code{foo} which expands to @code{0000}; we
-then use the @code{m4} builtin @code{defn} to define @code{bar} as the
+then use the @code{m4} built-in @code{defn} to define @code{bar} as the
same thing. However, when we change the open quote string to
@code{<QUOTE>} and the close quote string to @code{<UNQUOTE>}, the same
procedure fails to define a new synonym @code{baz}:
@smallexample
$ @i{_GDBP__ m4}
-Reading symbol data from m4...done.
-(_GDBP__)
+@c FIXME: this falsifies the exact text played out, to permit smallbook
+@c FIXME... format to come out better.
+GDB is free software and you are welcome to distribute copies
+ of it under certain conditions; type "show copying" to see
+ the conditions.
+There is absolutely no warranty for GDB; type "show warranty"
+for details.
+GDB _GDB_VN__, Copyright 1991 Free Software Foundation, Inc...
+(_GDBP__)
@end smallexample
@noindent
-_GDBN__ reads only enough symbol data to know where to find the rest
-when needed; as a result, the first prompt comes up very quickly. We
-then tell _GDBN__ to use a narrower display width than usual, so
-that examples will fit in this manual.
+_GDBN__ reads only enough symbol data to know where to find the
+rest when needed; as a result, the first prompt comes up very
+quickly. We now tell _GDBN__ to use a narrower display width than
+usual, so that examples will fit in this manual.@refill
@smallexample
(_GDBP__) @i{set width 70}
@end smallexample
-@noindent
-Let's see how the @code{m4} builtin @code{changequote} works.
+@noindent
+Let's see how the @code{m4} built-in @code{changequote} works.
Having looked at the source, we know the relevant subroutine is
@code{m4_changequote}, so we set a breakpoint there with _GDBN__'s
@code{break} command.
@smallexample
(_GDBP__) @i{run}
-Starting program: /work/Editorial/gdb/gnu/m4/m4
+Starting program: /work/Editorial/gdb/gnu/m4/m4
@i{define(foo,0000)}
@i{foo}
@smallexample
@i{changequote(<QUOTE>,<UNQUOTE>)}
-Breakpoint 1, m4_changequote (argc=3, argv=0x33c70) at builtin.c:879
+Breakpoint 1, m4_changequote (argc=3, argv=0x33c70)
+ at builtin.c:879
879 if (bad_argc(TOKEN_DATA_TEXT(argv[0]), argc, 1, 3))
@end smallexample
@smallexample
(_GDBP__) @i{n}
-882 set_quotes((argc >= 2) ? TOKEN_DATA_TEXT(argv[1]) : nil,
+882 set_quotes((argc >= 2) ? TOKEN_DATA_TEXT(argv[1])\
+ : nil,
@end smallexample
@noindent
@code{set_quotes} looks like a promising subroutine. We can go into it
by using the command @code{s} (@code{step}) instead of @code{next}.
@code{step} goes to the next line to be executed in @emph{any}
-subroutine, so it steps into @code{set_quotes}.
+subroutine, so it steps into @code{set_quotes}.
@smallexample
(_GDBP__) @i{s}
@end smallexample
@noindent
-The summary display showing the subroutine where @code{m4} is now
-suspended (and its arguments) is called a stack frame display. We can
-use the @code{backtrace} command (which can also be spelled @code{bt}),
-to see where we are in the stack: it displays a stack frame for each
-active subroutine.
+The display that shows the subroutine where @code{m4} is now
+suspended (and its arguments) is called a stack frame display. It
+shows a summary of the stack. We can use the @code{backtrace}
+command (which can also be spelled @code{bt}), to see where we are
+in the stack as a whole: the @code{backtrace} command displays a
+stack frame for each active subroutine.
@smallexample
(_GDBP__) @i{bt}
#0 set_quotes (lq=0x34c78 "<QUOTE>", rq=0x34c88 "<UNQUOTE>")
at input.c:530
-#1 0x6344 in m4_changequote (argc=3, argv=0x33c70) at builtin.c:882
+#1 0x6344 in m4_changequote (argc=3, argv=0x33c70)
+ at builtin.c:882
#2 0x8174 in expand_macro (sym=0x33320) at macro.c:242
#3 0x7a88 in expand_token (obs=0x0, t=209696, td=0xf7fffa30)
at macro.c:71
(_GDBP__) @i{s}
0x3b5c 532 if (rquote != def_rquote)
(_GDBP__) @i{s}
-0x3b80 535 lquote = (lq == nil || *lq == '\0') ? def_lquote :\
- xstrdup(lq);
+0x3b80 535 lquote = (lq == nil || *lq == '\0') ? \
+def_lquote : xstrdup(lq);
(_GDBP__) @i{n}
-536 rquote = (rq == nil || *rq == '\0') ? def_rquote : xstrdup\
-(rq);
+536 rquote = (rq == nil || *rq == '\0') ? def_rquote\
+ : xstrdup(rq);
(_GDBP__) @i{n}
538 len_lquote = strlen(rquote);
@end smallexample
@smallexample
(_GDBP__) @i{l}
533 xfree(rquote);
-534
-535 lquote = (lq == nil || *lq == '\0') ? def_lquote : xstrdup\
-(lq);
-536 rquote = (rq == nil || *rq == '\0') ? def_rquote : xstrdup\
-(rq);
-537
+534
+535 lquote = (lq == nil || *lq == '\0') ? def_lquote\
+ : xstrdup (lq);
+536 rquote = (rq == nil || *rq == '\0') ? def_rquote\
+ : xstrdup (rq);
+537
538 len_lquote = strlen(rquote);
539 len_rquote = strlen(lquote);
540 @}
-541
+541
542 void
@end smallexample
@code{rquote} respectively. Let's try setting them to better values.
We can use the @code{p} command for this, since it'll print the value of
any expression---and that expression can include subroutine calls and
-assignments.
+assignments.
@smallexample
(_GDBP__) p len_lquote=strlen(lquote)
Program exited normally.
@end smallexample
-@noindent
+@noindent
The message @samp{Program exited normally.} is from _GDBN__; it
indicates @code{m4} has finished executing. We can end our _GDBN__
session with the _GDBN__ @code{quit} command.
@node Invocation, Commands, Sample Session, Top
@chapter Getting In and Out of _GDBN__
+Type @kbd{gdb} or @kbd{gdb @var{program} @var{core}} to start GDB
+and type @kbd{quit} or @kbd{C-d} to exit.
+
@menu
-* Starting _GDBN__:: Starting _GDBN__
-* Leaving _GDBN__:: Leaving _GDBN__
-* Shell Commands:: Shell Commands
+* Invoking _GDBN__:: Starting _GDBN__
+* Leaving _GDBN__:: Leaving _GDBN__
+* Shell Commands:: Shell Commands
@end menu
-@node Starting _GDBN__, Leaving _GDBN__, Invocation, Invocation
+@node Invoking _GDBN__, Leaving _GDBN__, Invocation, Invocation
@section Starting _GDBN__
-_GDBN__ is invoked with the shell command @code{_GDBP__}. Once started,
+Invoke _GDBN__ with the shell command @code{_GDBP__}. Once started,
it reads commands from the terminal until you tell it to exit.
You can run @code{_GDBP__} with no arguments or options; but the most
usual way to start _GDBN__ is with one argument or two, specifying an
executable program as the argument:
@example
-_GDBP__ program
+_GDBP__ @var{program}
@end example
@noindent
-You can also start with both an executable program and a core file specified:
+You can also start with both an executable program and a core file
+specified:
+@example
+_GDBP__ @var{program} @var{core}
+@end example
+
+You can, instead, specify a process ID as a second argument, if you want
+to debug a running process:
@example
-_GDBP__ program core
+_GDBP__ @var{program} 1234
@end example
+@noindent
+would attach _GDBN__ to process @code{1234} (unless you also have a file
+named @file{1234}; _GDBN__ does check for a core file first).
@noindent
You can further control how _GDBN__ starts up by using command-line
-options. _GDBN__ itself can remind you of the options available:
+options. _GDBN__ itself can remind you of the options available.
+
+@noindent
+Type
+
@example
_GDBP__ -help
@end example
+
@noindent
-will display all available options and briefly describe their use
+to display all available options and briefly describe their use
(@samp{_GDBP__ -h} is a shorter equivalent).
All options and command line arguments you give are processed
in sequential order. The order makes a difference when the
-@samp{-x} option is used.
+@samp{-x} option is used.
@menu
-* File Options:: Choosing Files
-* Mode Options:: Choosing Modes
+* File Options:: Choosing Files
+* Mode Options:: Choosing Modes
_if__(!_GENERIC__)
_include__(gdbinv-m.m4)_dnl__
_fi__(!_GENERIC__)
@end menu
-@node File Options, Mode Options, Starting _GDBN__, Starting _GDBN__
+@node File Options, Mode Options, Invoking _GDBN__, Invoking _GDBN__
@subsection Choosing Files
-As shown above, any arguments other than options specify an executable
-file and core file; that is, the first argument encountered with no
-associated option flag is equivalent to a @samp{-se} option, and the
-second, if any, is equivalent to a @samp{-c} option. Many options have
-both long and short forms; both are shown here. The long forms are also
-recognized if you truncate them, so long as enough of the option is
-present to be unambiguous. (If you prefer, you can flag option
-arguments with @samp{+} rather than @samp{-}, though we illustrate the
-more usual convention.)
+When _GDBN__ starts, it reads any arguments other than options as
+specifying an executable file and core file (or process ID). This is
+the same as if the arguments were specified by the @samp{-se} and
+@samp{-c} options respectively. (_GDBN__ reads the first argument
+that does not have an associated option flag as equivalent to the
+@samp{-se} option followed by that argument; and the second argument
+that does not have an associated option flag, if any, as equivalent to
+the @samp{-c} option followed by that argument.)
+
+Many options have both long and short forms; both are shown in the
+following list. _GDBN__ also recognizes the long forms if you truncate
+them, so long as enough of the option is present to be unambiguous.
+(If you prefer, you can flag option arguments with @samp{--} rather
+than @samp{-}, though we illustrate the more usual convention.)
@table @code
@item -symbols=@var{file}
@end table
_if__(!_GENERIC__)
-@node Mode Options, i960-Nindy Remote, File Options, Starting _GDBN__
+@node Mode Options, Mode Options, File Options, Invoking _GDBN__
_fi__(!_GENERIC__)
_if__(_GENERIC__)
-@node Mode Options, , File Options, Starting _GDBN__
-_fi__(_GENERIC__)
+@node Mode Options, , File Options, Invoking _GDBN__
+_fi__(_GENERIC__)
+You can run _GDBN__ in various alternative modes---for example, in
+batch mode or quiet mode.
@subsection Choosing Modes
@table @code
@itemx -n
Do not execute commands from any @file{_GDBINIT__} initialization files.
Normally, the commands in these files are executed after all the
-command options and arguments have been processed. @xref{Command
-Files}.
+command options and arguments have been processed.
+@xref{Command Files}.
@item -quiet
@itemx -q
``Quiet''. Do not print the introductory and copyright messages. These
-messages are also suppressed in batch mode, or if an executable file name is
-specified on the _GDBN__ command line.
+messages are also suppressed in batch mode.
@item -batch
Run in batch mode. Exit with status @code{0} after processing all the command
files specified with @samp{-x} (and @file{_GDBINIT__}, if not inhibited).
Exit with nonzero status if an error occurs in executing the _GDBN__
-commands in the command files.
+commands in the command files.
Batch mode may be useful for running _GDBN__ as a filter, for example to
download and run a program on another computer; in order to make this
-more useful, the message
+more useful, the message
@example
Program exited normally.
@end example
Emacs sets this option when it runs _GDBN__ as a subprocess. It tells _GDBN__
to output the full file name and line number in a standard,
recognizable fashion each time a stack frame is displayed (which
-includes each time the program stops). This recognizable format looks
+includes each time your program stops). This recognizable format looks
like two @samp{\032} characters, followed by the file name, line number
and character position separated by colons, and a newline. The
Emacs-to-_GDBN__ interface program uses the two @samp{\032} characters as
@item -tty=@var{device}
Run using @var{device} for your program's standard input and output.
-@c FIXME: kingdon thinks there's more to -tty. Investigate.
+@c FIXME: kingdon thinks there is more to -tty. Investigate.
@end table
_if__(!_GENERIC__)
_include__(gdbinv-s.m4)
_fi__(!_GENERIC__)
-@node Leaving _GDBN__, Shell Commands, Starting _GDBN__, Invocation
+@node Leaving _GDBN__, Shell Commands, Invoking _GDBN__, Invocation
@section Leaving _GDBN__
@cindex exiting _GDBN__
@table @code
@kindex quit
@kindex q
To exit _GDBN__, use the @code{quit} command (abbreviated @code{q}), or type
-an end-of-file character (usually @kbd{C-d}).
+an end-of-file character (usually @kbd{C-d}).
@end table
@cindex interrupt
until a time when it is safe.
If you've been using _GDBN__ to control an attached process or device,
-you can release it with the @code{detach} command; @pxref{Attach}.
+you can release it with the @code{detach} command; @pxref{Attach, ,Debugging an Already-Running Process}..
@node Shell Commands, , Leaving _GDBN__, Invocation
@section Shell Commands
If you need to execute occasional shell commands during your
-debugging session, there's no need to leave or suspend _GDBN__; you can
+debugging session, there is no need to leave or suspend _GDBN__; you can
just use the @code{shell} command.
@table @code
@end table
The utility @code{make} is often needed in development environments.
-You don't have to use the @code{shell} command for this purpose in _GDBN__:
+You do not have to use the @code{shell} command for this purpose in _GDBN__:
@table @code
@item make @var{make-args}
@node Commands, Running, Invocation, Top
@chapter _GDBN__ Commands
+You can abbreviate GDB command if that abbreviation is unambiguous;
+and you can repeat certain GDB commands by typing just @key{RET}.
+
@menu
-* Command Syntax:: Command Syntax
-* Help:: Getting Help
+* Command Syntax:: Command Syntax
+* Help:: Getting Help
@end menu
@node Command Syntax, Help, Commands, Commands
names start with @code{s}. You can test abbreviations by using them as
arguments to the @code{help} command.
-@cindex repeating commands
+@cindex repeating commands
@kindex RET
A blank line as input to _GDBN__ (typing just @key{RET}) means to
repeat the previous command. Certain commands (for example, @code{run})
@key{RET}, construct new arguments rather than repeating
exactly as typed. This permits easy scanning of source or memory.
+_GDBN__ can also use @key{RET} in another way: to partition lengthy
+output, in a way similar to the common utility @code{more}
+(@pxref{Screen Size}). Since it is easy to press one @key{RET} too many
+in this situation, _GDBN__ disables command repetition after any command
+that generates this sort of display.
+
@kindex #
@cindex comment
A line of input starting with @kbd{#} is a comment; it does nothing.
-This is useful mainly in command files (@xref{Command Files}).
+This is useful mainly in command files (@pxref{Command Files}).
@node Help, , Command Syntax, Commands
@section Getting Help
@cindex online documentation
@kindex help
You can always ask _GDBN__ itself for information on its commands, using the
-command @code{help}.
+command @code{help}.
@table @code
@item help
aliases -- Aliases of other commands
obscure -- Obscure features
-Type "help" followed by a class name for a list of commands in that class.
-Type "help" followed by command name for full documentation.
+Type "help" followed by a class name for a list of
+commands in that class.
+Type "help" followed by command name for full
+documentation.
Command name abbreviations are allowed if unambiguous.
-(_GDBP__)
+(_GDBP__)
@end smallexample
@item help @var{class}
show -- Generic command for showing things set with "set"
info -- Generic command for printing status
-Type "help" followed by command name for full documentation.
+Type "help" followed by command name for full
+documentation.
Command name abbreviations are allowed if unambiguous.
-(_GDBP__)
+(_GDBP__)
@end smallexample
@item help @var{command}
With a command name as @code{help} argument, _GDBN__ will display a
-short paragraph on how to use that command.
+short paragraph on how to use that command.
@end table
In addition to @code{help}, you can use the _GDBN__ commands @code{info}
of _GDBN__ itself. Each command supports many topics of inquiry; this
manual introduces each of them in the appropriate context. The listings
under @code{info} and under @code{show} in the Index point to
-all the sub-commands.
-@c FIXME: @pxref{Index} used to be here, but even though it shows up in
-@c FIXME...the 'aux' file with a pageno the xref can't find it.
+all the sub-commands. @xref{Index}.
@c @group
@table @code
You can change most of the things you can @code{show}, by using the
related command @code{set}; for example, you can control what number
system is used for displays with @code{set radix}, or simply inquire
-which is currently in use with @code{show radix}.
+which is currently in use with @code{show radix}.
@kindex info set
To display all the settable parameters and their current
Show what version of _GDBN__ is running. You should include this
information in _GDBN__ bug-reports. If multiple versions of _GDBN__ are
in use at your site, you may occasionally want to make sure what version
-of _GDBN__ you're running; as _GDBN__ evolves, new commands are
+of _GDBN__ you are running; as _GDBN__ evolves, new commands are
introduced, and old ones may wither away. The version number is also
announced when you start _GDBN__ with no arguments.
@chapter Running Programs Under _GDBN__
@menu
-* Compilation:: Compiling for Debugging
-* Starting:: Starting your Program
-* Arguments:: Your Program's Arguments
-* Environment:: Your Program's Environment
-* Working Directory:: Your Program's Working Directory
-* Input/Output:: Your Program's Input and Output
-* Attach:: Debugging an Already-Running Process
-* Kill Process:: Killing the Child Process
+* Compilation:: Compiling for Debugging
+* Starting:: Starting your Program
+* Arguments:: Your Program's Arguments
+* Environment:: Your Program's Environment
+* Working Directory:: Your Program's Working Directory
+* Input/Output:: Your Program's Input and Output
+* Attach:: Debugging an Already-Running Process
+* Kill Process:: Killing the Child Process
@end menu
@node Compilation, Starting, Running, Running
The GNU C compiler supports @samp{-g} with or without @samp{-O}, making it
possible to debug optimized code. We recommend that you @emph{always} use
-@samp{-g} whenever you compile a program. You may think the program is
-correct, but there's no sense in pushing your luck.
+@samp{-g} whenever you compile a program. You may think your program is
+correct, but there is no sense in pushing your luck.
Some things do not work as well with @samp{-g -O} as with just
@samp{-g}, particularly on machines with instruction scheduling. If in
If your program includes archives made with the @code{ar} program, and
if the object files used as input to @code{ar} were compiled without the
@samp{-g} option and have names longer than 15 characters, _GDBN__ will get
-confused reading the program's symbol table. No error message will be
+confused reading your program's symbol table. No error message will be
given, but _GDBN__ may behave strangely. The reason for this problem is a
deficiency in the Unix archive file format, which cannot represent file
names longer than 15 characters.
@code{ar} dated more recently than August 1989.
@end ignore
-
@node Starting, Arguments, Compilation, Running
@section Starting your Program
@cindex starting
@kindex run
Use the @code{run} command to start your program under _GDBN__. You
must first specify the program name
-_if__(_VXWORKS__)
+_if__(_VXWORKS__)
(except on VxWorks)
_fi__(_VXWORKS__)
with an argument to _GDBN__
-(@pxref{Invocation}), or using the @code{file} or @code{exec-file}
-command (@pxref{Files}).
+(@pxref{Invocation, ,Getting In and Out of _GDBN__}), or using the @code{file} or @code{exec-file}
+command (@pxref{Files, ,Commands to Specify Files}).
@refill
@end table
-On targets that support processes, @code{run} creates an inferior
-process and makes that process run your program. On other targets,
-@code{run} jumps to the start of the program.
+If you are running your program in an execution environment that
+supports processes, @code{run} creates an inferior process and makes
+that process run your program. (In environments without processes,
+@code{run} jumps to the start of your program.)
The execution of a program is affected by certain information it
receives from its superior. _GDBN__ provides ways to specify this
-information, which you must do @i{before} starting the program. (You
-can change it after starting the program, but such changes will only affect
-the program the next time you start it.) This information may be
+information, which you must do @i{before} starting your program. (You
+can change it after starting your program, but such changes will only affect
+your program the next time you start it.) This information may be
divided into four categories:
@table @asis
@item The @i{arguments.}
-You specify the arguments to give your program as the arguments of the
-@code{run} command. If a shell is available on your target, the shell
-is used to pass the arguments, so that you may use normal conventions
-(such as wildcard expansion or variable substitution) in
-describing the arguments. In Unix systems, you can control which shell
-is used with the @code{SHELL} environment variable. @xref{Arguments}.@refill
+Specify the arguments to give your program as the arguments of the
+@code{run} command. If a shell is available on your target, the
+shell is used to pass the arguments, so that you may use normal
+conventions (such as wildcard expansion or variable substitution)
+in describing the arguments. In Unix systems, you can control
+which shell is used with the @code{SHELL} environment variable.
+@xref{Arguments, ,Your Program's Arguments}.@refill
@item The @i{environment.}
Your program normally inherits its environment from _GDBN__, but you can
use the _GDBN__ commands @code{set environment} and @code{unset
environment} to change parts of the environment that will be given to
-the program. @xref{Environment}.@refill
+your program. @xref{Environment, ,Your Program's Environment}.@refill
@item The @i{working directory.}
Your program inherits its working directory from _GDBN__. You can set
_GDBN__'s working directory with the @code{cd} command in _GDBN__.
-@xref{Working Directory}.
+@xref{Working Directory, ,Your Program's Working Directory}.
@item The @i{standard input and output.}
Your program normally uses the same device for standard input and
standard output as _GDBN__ is using. You can redirect input and output
in the @code{run} command line, or you can use the @code{tty} command to
set a different device for your program.
-@xref{Input/Output}.
+@xref{Input/Output, Your Program's Input and Output}.
@cindex pipes
-@emph{Warning:} While input and output redirection work, you can't use
-pipes to pass the output of the program you're debugging to another
+@emph{Warning:} While input and output redirection work, you cannot use
+pipes to pass the output of the program you are debugging to another
program; if you attempt this, _GDBN__ is likely to wind up debugging the
wrong program.
@end table
-When you issue the @code{run} command, your program begins to execute
-immediately. @xref{Stopping}, for discussion of how to arrange for your
-program to stop. Once your program has been started by the @code{run}
-command (and then stopped), you may evaluate expressions that involve
-calls to functions in the inferior, using the @code{print} or
-@code{call} commands. @xref{Data}.
+@c FIXME: Rewrite following paragraph, especially its third sentence.
+When you issue the @code{run} command, your program begins to
+execute immediately. @xref{Stopping, ,Stopping and Continuing}, for
+discussion of how to arrange for your program to stop. Once your
+program has been started by the @code{run} command (and then stopped),
+you may evaluate expressions that involve calls to functions in the
+inferior, using the @code{print} or @code{call} commands. @xref{Data,
+,Examining Data}.
-If the modification time of your symbol file has changed since the last
-time _GDBN__ read its symbols, _GDBN__ will discard its symbol table and re-read
-it. In this process, it tries to retain your current breakpoints.
+If the modification time of your symbol file has changed since the
+last time _GDBN__ read its symbols, _GDBN__ will discard its symbol
+table and re-read it. When it does this, _GDBN__ tries to retain your
+current breakpoints.
@node Arguments, Environment, Starting, Running
@section Your Program's Arguments
@cindex arguments (to your program)
The arguments to your program can be specified by the arguments of the
@code{run} command. They are passed to a shell, which expands wildcard
-characters and performs redirection of I/O, and thence to the program.
+characters and performs redirection of I/O, and thence to your program.
_GDBN__ uses the shell indicated by your environment variable
@code{SHELL} if it exists; otherwise, _GDBN__ uses @code{/bin/sh}.
@item set args
Specify the arguments to be used the next time your program is run. If
@code{set args} has no arguments, @code{run} will execute your program
-with no arguments. Once you have run your program with arguments,
+with no arguments. Once you have run your program with arguments,
using @code{set args} before the next @code{run} is the only way to run
it again without arguments.
your user name, your home directory, your terminal type, and your search
path for programs to run. Usually you set up environment variables with
the shell and they are inherited by all the other programs you run. When
-debugging, it can be useful to try running the program with a modified
+debugging, it can be useful to try running your program with a modified
environment without having to start _GDBN__ over again.
@table @code
(the search path for executables), for both _GDBN__ and your program.
You may specify several directory names, separated by @samp{:} or
whitespace. If @var{directory} is already in the path, it is moved to
-the front, so it will be searched sooner.
+the front, so it will be searched sooner.
You can use the string @samp{$cwd} to refer to whatever is the current
working directory at the time _GDBN__ searches the path. If you use
@samp{.} instead, it refers to the directory where you executed the
@code{path} command. _GDBN__ fills in the current path where needed in
the @var{directory} argument, before adding it to the search path.
-@c 'path' is explicitly nonrepeatable, but RMS points out it's silly to
+@c 'path' is explicitly nonrepeatable, but RMS points out it is silly to
@c document that, since repeating it would be a no-op.
@item show paths
@item show environment @r{[}@var{varname}@r{]}
@kindex show environment
Print the value of environment variable @var{varname} to be given to
-your program when it starts. If you don't supply @var{varname},
+your program when it starts. If you do not supply @var{varname},
print the names and values of all environment variables to be given to
your program. You can abbreviate @code{environment} as @code{env}.
any interpretation is supplied by your program itself. The @var{value}
parameter is optional; if it is eliminated, the variable is set to a
null value.
-@c "any string" here doesn't include leading, trailing
+@c "any string" here does not include leading, trailing
@c blanks. Gnu asks: does anyone care?
For example, this command:
Remove variable @var{varname} from the environment to be passed to your
program. This is different from @samp{set env @var{varname} =};
@code{unset environment} removes the variable from the environment,
-rather than assigning it an empty value.
+rather than assigning it an empty value.
@end table
@node Working Directory, Input/Output, Environment, Running
directory in _GDBN__ with the @code{cd} command.
The _GDBN__ working directory also serves as a default for the commands
-that specify files for _GDBN__ to operate on. @xref{Files}.
+that specify files for _GDBN__ to operate on. @xref{Files, ,Commands to Specify Files}.
@table @code
@item cd @var{directory}
program is using.
@end table
-You can redirect the program's input and/or output using shell
+You can redirect your program's input and/or output using shell
redirection with the @code{run} command. For example,
_0__@example
_1__@end example
@noindent
-starts the program, diverting its output to the file @file{outfile}.
+starts your program, diverting its output to the file @file{outfile}.
@kindex tty
@cindex controlling terminal
-Another way to specify where the program should do input and output is
+Another way to specify where your program should do input and output is
with the @code{tty} command. This command accepts a file name as
argument, and causes this file to be the default for future @code{run}
commands. It also resets the controlling terminal for the child
(@code{info files} will show your active targets.) The command takes as
argument a process ID. The usual way to find out the process-id of
a Unix process is with the @code{ps} utility, or with the @samp{jobs -l}
-shell command.
+shell command.
@code{attach} will not repeat if you press @key{RET} a second time after
executing the command.
When using @code{attach}, you should first use the @code{file} command
to specify the program running in the process and load its symbol table.
-@xref{Files}.
+@xref{Files, ,Commands to Specify Files}.
The first thing _GDBN__ does after arranging to debug the specified
process is to stop it. You can examine and modify an attached process
process, you kill that process. By default, you will be asked for
confirmation if you try to do either of these things; you can control
whether or not you need to confirm by using the @code{set confirm} command
-(@pxref{Messages/Warnings}).
+(@pxref{Messages/Warnings, ,Optional Warnings and Messages}).
@node Kill Process, , Attach, Running
@c @group
is running.
@c @end group
-On some operating systems, a program can't be executed outside _GDBN__
+On some operating systems, a program cannot be executed outside _GDBN__
while you have breakpoints set on it inside _GDBN__. You can use the
-@code{kill} command in this situation to permit running the program
+@code{kill} command in this situation to permit running your program
outside the debugger.
The @code{kill} command is also useful if you wish to recompile and
-relink the program, since on many systems it is impossible to modify an
+relink your program, since on many systems it is impossible to modify an
executable file while it is running in a process. In this case, when you
next type @code{run}, _GDBN__ will notice that the file has changed, and
will re-read the symbol table (while trying to preserve your current
@chapter Stopping and Continuing
The principal purpose of using a debugger is so that you can stop your
-program before it terminates; or so that, if the program runs into
+program before it terminates; or so that, if your program runs into
trouble, you can investigate and find out why.
Inside _GDBN__, your program may stop for any of several reasons, such
@end table
@menu
-* Breakpoints:: Breakpoints, Watchpoints, and Exceptions
-* Continuing and Stepping:: Resuming Execution
-* Signals:: Signals
+* Breakpoints:: Breakpoints, Watchpoints, and Exceptions
+* Continuing and Stepping:: Resuming Execution
+* Signals:: Signals
@end menu
@node Breakpoints, Continuing and Stepping, Stopping, Stopping
@cindex breakpoints
A @dfn{breakpoint} makes your program stop whenever a certain point in
-the program is reached. For each breakpoint, you can add various
-conditions to control in finer detail whether the program will stop.
+your program is reached. For each breakpoint, you can add various
+conditions to control in finer detail whether your program will stop.
You can set breakpoints with the @code{break} command and its variants
-(@pxref{Set Breaks}), to specify the place where the program should stop
-by line number, function name or exact address in the program. In
-languages with exception handling (such as GNU C++), you can also set
-breakpoints where an exception is raised (@pxref{Exception Handling}).
+(@pxref{Set Breaks, ,Setting Breakpoints}), to specify the place where
+your program should stop by line number, function name or exact address
+in your program. In languages with exception handling (such as GNU
+C++), you can also set breakpoints where an exception is raised
+(@pxref{Exception Handling, ,Breakpoints and Exceptions}).@refill
@cindex watchpoints
-A @dfn{watchpoint} is a special breakpoint that stops your program when
-the value of an expression changes. You must use a different command to
-set watchpoints (@pxref{Set Watchpoints}), but aside from that, you can
-manage a watchpoint like any other breakpoint: you enable, disable, and
-delete both breakpoints and watchpoints using the same commands.
+A @dfn{watchpoint} is a special breakpoint that stops your program
+when the value of an expression changes. You must use a different
+command to set watchpoints (@pxref{Set Watchpoints, ,Setting
+Watchpoints}), but aside from that, you can manage a watchpoint like
+any other breakpoint: you enable, disable, and delete both breakpoints
+and watchpoints using the same commands.@refill
Each breakpoint or watchpoint is assigned a number when it is created;
these numbers are successive integers starting with one. In many of the
commands for controlling various features of breakpoints you use the
breakpoint number to say which breakpoint you want to change. Each
breakpoint may be @dfn{enabled} or @dfn{disabled}; if disabled, it has
-no effect on the program until you enable it again.
+no effect on your program until you enable it again.
@menu
-* Set Breaks:: Setting Breakpoints
-* Set Watchpoints:: Setting Watchpoints
-* Exception Handling:: Breakpoints and Exceptions
-* Delete Breaks:: Deleting Breakpoints
-* Disabling:: Disabling Breakpoints
-* Conditions:: Break Conditions
-* Break Commands:: Breakpoint Command Lists
-* Breakpoint Menus:: Breakpoint Menus
-* Error in Breakpoints::
+* Set Breaks:: Setting Breakpoints
+* Set Watchpoints:: Setting Watchpoints
+* Exception Handling:: Breakpoints and Exceptions
+* Delete Breaks:: Deleting Breakpoints
+* Disabling:: Disabling Breakpoints
+* Conditions:: Break Conditions
+* Break Commands:: Breakpoint Command Lists
+* Breakpoint Menus:: Breakpoint Menus
+* Error in Breakpoints::
@end menu
@node Set Breaks, Set Watchpoints, Breakpoints, Breakpoints
@subsection Setting Breakpoints
+@c FIXME LMB what does GDB do if no code on line of breakpt?
+@c consider in particular declaration with/without initialization.
+@c
+@c FIXME 2 is there stuff on this already? break at fun start, already init?
+
@kindex break
@kindex b
Breakpoints are set with the @code{break} command (abbreviated @code{b}).
@item break @var{linenum}
Set a breakpoint at line @var{linenum} in the current source file.
That file is the last file whose source text was printed. This
-breakpoint will stop the program just before it executes any of the
+breakpoint will stop your program just before it executes any of the
code on that line.
@item break @var{filename}:@var{linenum}
@item break *@var{address}
Set a breakpoint at address @var{address}. You can use this to set
-breakpoints in parts of the program which do not have debugging
+breakpoints in parts of your program which do not have debugging
information or source files.
@item break
-When called without any arguments, @code{break} sets a breakpoint at the
-next instruction to be executed in the selected stack frame
-(@pxref{Stack}). In any selected frame but the innermost, this will
-cause the program to stop as soon as control returns to that frame.
-This is similar to the effect of a @code{finish} command in the frame
-inside the selected frame---except that @code{finish} doesn't leave an
-active breakpoint. If you use @code{break} without an argument in the
-innermost frame, _GDBN__ will stop the next time it reaches the current
-location; this may be useful inside loops.
+When called without any arguments, @code{break} sets a breakpoint at
+the next instruction to be executed in the selected stack frame
+(@pxref{Stack, ,Examining the Stack}). In any selected frame but the
+innermost, this will cause your program to stop as soon as control
+returns to that frame. This is similar to the effect of a
+@code{finish} command in the frame inside the selected frame---except
+that @code{finish} does not leave an active breakpoint. If you use
+@code{break} without an argument in the innermost frame, _GDBN__ will
+stop the next time it reaches the current location; this may be useful
+inside loops.@refill
_GDBN__ normally ignores breakpoints when it resumes execution, until at
least one instruction has been executed. If it did not do this, you
would be unable to proceed past a breakpoint without first disabling the
breakpoint. This rule applies whether or not the breakpoint already
-existed when the program stopped.
+existed when your program stopped.
@item break @dots{} if @var{cond}
Set a breakpoint with condition @var{cond}; evaluate the expression
@var{cond} each time the breakpoint is reached, and stop only if the
value is nonzero---that is, if @var{cond} evaluates as true.
@samp{@dots{}} stands for one of the possible arguments described above
-(or no argument) specifying where to break. @xref{Conditions}, for more
-information on breakpoint conditions.
+(or no argument) specifying where to break. @xref{Conditions, ,Break
+Conditions}, for more information on breakpoint conditions.
@item tbreak @var{args}
@kindex tbreak
Set a breakpoint enabled only for one stop. @var{args} are the
same as for the @code{break} command, and the breakpoint is set in the same
-way, but the breakpoint is automatically disabled the first time it
-is hit. @xref{Disabling}.
+way, but the breakpoint is automatically disabled after the first time your
+program stops there. @xref{Disabling, ,Disabling Breakpoints}.
@item rbreak @var{regex}
@kindex rbreak
@cindex regular expression
-@c FIXME: 2nd sentence below C++ only?
+@c FIXME what kind of regexp?
Set breakpoints on all functions matching the regular expression
-@var{regex}. This is useful for setting breakpoints on overloaded
-functions that are not members of any special classes. This command
+@var{regex}. This command
sets an unconditional breakpoint on all matches, printing a list of all
breakpoints it set. Once these breakpoints are set, they are treated
just like the breakpoints set with the @code{break} command. They can
be deleted, disabled, made conditional, etc., in the standard ways.
+When debugging C++ programs, @code{rbreak} is useful for setting
+breakpoints on overloaded functions that are not members of any special
+classes.
+
@kindex info breakpoints
-@kindex $_
+@cindex @code{$_} and @code{info breakpoints}
@item info breakpoints @r{[}@var{n}@r{]}
@item info break @r{[}@var{n}@r{]}
Print a list of all breakpoints (but not watchpoints) set and not
-deleted, showing their numbers, where in the program they are, and any
+deleted, showing their numbers, where in your program they are, and any
special features in use for them. Disabled breakpoints are included in
the list, but marked as disabled. @code{info break} with a breakpoint
-number @var{n} as argument lists only that breakpoint. The convenience
-variable @code{$_} and the default examining-address for the @code{x}
-command are set to the address of the last breakpoint listed
-(@pxref{Memory}). The equivalent command for watchpoints is @code{info
-watch}. @end table
+number @var{n} as argument lists only that breakpoint. The
+convenience variable @code{$_} and the default examining-address for
+the @code{x} command are set to the address of the last breakpoint
+listed (@pxref{Memory, ,Examining Memory}). The equivalent command
+for watchpoints is @code{info watch}. @end table
-_GDBN__ allows you to set any number of breakpoints at the same place in the
-program. There is nothing silly or meaningless about this. When the
-breakpoints are conditional, this is even useful (@pxref{Conditions}).
+_GDBN__ allows you to set any number of breakpoints at the same place
+in your program. There is nothing silly or meaningless about this.
+When the breakpoints are conditional, this is even useful
+(@pxref{Conditions, ,Break Conditions}).
@node Set Watchpoints, Exception Handling, Set Breaks, Breakpoints
@subsection Setting Watchpoints
@cindex setting watchpoints
You can use a watchpoint to stop execution whenever the value of an
-expression changes, without having to predict a particular place
+expression changes, without having to predict a particular place
where this may happen.
Watchpoints currently execute two orders of magnitude more slowly than
releases of _GDBN__ will use such hardware if it is available.
@table @code
-@kindex watch
+@kindex watch
@item watch @var{expr}
Set a watchpoint for an expression.
@subsection Breakpoints and Exceptions
@cindex exception handlers
-Some languages, such as GNU C++, implement exception handling. _GDBN__
-can be used to examine what caused the program to raise an exception
-and to list the exceptions the program is prepared to handle at a
+Some languages, such as GNU C++, implement exception handling. You can
+use _GDBN__ to examine what caused your program to raise an exception,
+and to list the exceptions your program is prepared to handle at a
given point in time.
@table @code
to catch.
@end table
-You can use @code{info catch} to list active exception handlers;
-@pxref{Frame Info}.
+You can use @code{info catch} to list active exception handlers.
+@xref{Frame Info, ,Information About a Frame}.
There are currently some limitations to exception handling in _GDBN__.
These will be corrected in a future release.
If you call a function interactively, _GDBN__ normally returns
control to you when the function has finished executing. If the call
raises an exception, however, the call may bypass the mechanism that
-returns control to the user and cause the program to simply continue
+returns control to you and cause your program to simply continue
running until it hits a breakpoint, catches a signal that _GDBN__ is
listening for, or exits.
@item
@cindex raise exceptions
Sometimes @code{catch} is not the best way to debug exception handling:
-if you need to know exactly where an exception is raised, it's better to
+if you need to know exactly where an exception is raised, it is better to
stop @emph{before} the exception handler is called, since that way you
can see the stack before any unwinding takes place. If you set a
breakpoint in an exception handler instead, it may not be easy to find
out where the exception was raised.
To stop just before an exception handler is called, you need some
-knowledge of the implementation. In the case of GNU C++ exceptions are
+knowledge of the implementation. In the case of GNU C++, exceptions are
raised by calling a library function named @code{__raise_exception}
which has the following ANSI C interface:
@example
- /* ADDR is where the exception identifier is stored.
+ /* @var{addr} is where the exception identifier is stored.
ID is the exception identifier. */
void __raise_exception (void **@var{addr}, void *@var{id});
@end example
@noindent
To make the debugger catch all exceptions before any stack
unwinding takes place, set a breakpoint on @code{__raise_exception}
-(@pxref{Breakpoints}).
+(@pxref{Breakpoints, ,Breakpoints Watchpoints and Exceptions}).
-With a conditional breakpoint (@xref{Conditions}) that depends on the
-value of @var{id}, you can stop your program when a specific exception
-is raised. You can use multiple conditional breakpoints to stop the
-program when any of a number of exceptions are raised.
+With a conditional breakpoint (@pxref{Conditions, ,Break Conditions})
+that depends on the value of @var{id}, you can stop your program when
+a specific exception is raised. You can use multiple conditional
+breakpoints to stop your program when any of a number of exceptions are
+raised.
@node Delete Breaks, Disabling, Exception Handling, Breakpoints
@subsection Deleting Breakpoints
@cindex clearing breakpoints, watchpoints
@cindex deleting breakpoints, watchpoints
It is often necessary to eliminate a breakpoint or watchpoint once it
-has done its job and you no longer want the program to stop there. This
+has done its job and you no longer want your program to stop there. This
is called @dfn{deleting} the breakpoint. A breakpoint that has been
deleted no longer exists; it is forgotten.
With the @code{clear} command you can delete breakpoints according to
-where they are in the program. With the @code{delete} command you can
+where they are in your program. With the @code{delete} command you can
delete individual breakpoints or watchpoints by specifying their
breakpoint numbers.
@item clear
@kindex clear
Delete any breakpoints at the next instruction to be executed in the
-selected stack frame (@pxref{Selection}). When the innermost frame
-is selected, this is a good way to delete a breakpoint that the program
-just stopped at.
+selected stack frame (@pxref{Selection, ,Selecting a Frame}). When
+the innermost frame is selected, this is a good way to delete a
+breakpoint where your program just stopped.
@item clear @var{function}
@itemx clear @var{filename}:@var{function}
@code{enable} and @code{disable} commands, optionally specifying one or
more breakpoint numbers as arguments. Use @code{info break} or
@code{info watch} to print a list of breakpoints or watchpoints if you
-don't know which numbers to use.
+do not know which numbers to use.
A breakpoint or watchpoint can have any of four different states of
enablement:
@itemize @bullet
@item
-Enabled. The breakpoint will stop the program. A breakpoint set
+Enabled. The breakpoint will stop your program. A breakpoint set
with the @code{break} command starts out in this state.
@item
-Disabled. The breakpoint has no effect on the program.
+Disabled. The breakpoint has no effect on your program.
@item
-Enabled once. The breakpoint will stop the program, but
+Enabled once. The breakpoint will stop your program, but
when it does so it will become disabled. A breakpoint set
with the @code{tbreak} command starts out in this state.
@item
-Enabled for deletion. The breakpoint will stop the program, but
+Enabled for deletion. The breakpoint will stop your program, but
immediately after it does so it will be deleted permanently.
@end itemize
@kindex enable breakpoints
@kindex enable
Enable the specified breakpoints (or all defined breakpoints). They
-become effective once again in stopping the program.
+become effective once again in stopping your program.
@item enable @r{[}breakpoints@r{]} once @var{bnums}@dots{}
Enable the specified breakpoints temporarily. Each will be disabled
-again the next time it stops the program.
+again the next time it stops your program.
@item enable @r{[}breakpoints@r{]} delete @var{bnums}@dots{}
Enable the specified breakpoints to work once and then die. Each of
-the breakpoints will be deleted the next time it stops the program.
+the breakpoints will be deleted the next time it stops your program.
@end table
-Save for a breakpoint set with @code{tbreak} (@pxref{Set Breaks}),
-breakpoints that you set are initially enabled; subsequently, they become
-disabled or enabled only when you use one of the commands above. (The
-command @code{until} can set and delete a breakpoint of its own, but it
-will not change the state of your other breakpoints;
-@pxref{Continuing and Stepping}.)
+Save for a breakpoint set with @code{tbreak} (@pxref{Set Breaks,
+,Setting Breakpoints}), breakpoints that you set are initially
+enabled; subsequently, they become disabled or enabled only when you
+use one of the commands above. (The command @code{until} can set and
+delete a breakpoint of its own, but it will not change the state of
+your other breakpoints; @pxref{Continuing and Stepping}.)
@node Conditions, Break Commands, Disabling, Breakpoints
@subsection Break Conditions
@cindex conditional breakpoints
@cindex breakpoint conditions
-The simplest sort of breakpoint breaks every time the program reaches a
+@c FIXME what is scope of break condition expr? Context where wanted?
+@c in particular for a watchpoint?
+The simplest sort of breakpoint breaks every time your program reaches a
specified place. You can also specify a @dfn{condition} for a
breakpoint. A condition is just a Boolean expression in your
-programming language. (@xref{Expressions}). A breakpoint with a
-condition evaluates the expression each time the program reaches it, and
-the program stops only if the condition is @emph{true}.
+programming language (@pxref{Expressions}). A breakpoint with a condition
+evaluates the expression each time your program reaches it, and the
+program stops only if the condition is @emph{true}.
This is the converse of using assertions for program validation; in that
situation, you want to stop when the assertion is violated---that is,
when the condition is false. In C, if you want to test an assertion expressed
-by the condition @var{assert}, you should set the condition
+by the condition @var{assert}, you should set the condition
@samp{! @var{assert}} on the appropriate breakpoint.
Conditions are also accepted for watchpoints; you may not need them,
since a watchpoint is inspecting the value of an expression anyhow---but
it might be simpler, say, to just set a watchpoint on a variable name,
and specify a condition that tests whether the new value is an interesting
-one.
+one.
-Break conditions ca have side effects, and may even call functions in
+Break conditions can have side effects, and may even call functions in
your program. This can be useful, for example, to activate functions
-that log program progress, or to use your own print functions to format
-special data structures. The effects are completely predictable unless
-there is another enabled breakpoint at the same address. (In that
-case, _GDBN__ might see the other breakpoint first and stop the program
-without checking the condition of this one.) Note that breakpoint
-commands are usually more convenient and flexible for the purpose of
-performing side effects when a breakpoint is reached (@pxref{Break
-Commands}).
+that log program progress, or to use your own print functions to
+format special data structures. The effects are completely predictable
+unless there is another enabled breakpoint at the same address. (In
+that case, _GDBN__ might see the other breakpoint first and stop your
+program without checking the condition of this one.) Note that
+breakpoint commands are usually more convenient and flexible for the
+purpose of performing side effects when a breakpoint is reached
+(@pxref{Break Commands, ,Breakpoint Command Lists}).
Break conditions can be specified when a breakpoint is set, by using
-@samp{if} in the arguments to the @code{break} command. @xref{Set Breaks}.
-They can also be changed at any time with the @code{condition} command.
-The @code{watch} command doesn't recognize the @code{if} keyword;
-@code{condition} is the only way to impose a further condition on a
-watchpoint.
-
-@table @code
-@item condition @var{bnum} @var{expression}
-@kindex condition
+@samp{if} in the arguments to the @code{break} command. @xref{Set
+Breaks, ,Setting Breakpoints}. They can also be changed at any time
+with the @code{condition} command. The @code{watch} command does not
+recognize the @code{if} keyword; @code{condition} is the only way to
+impose a further condition on a watchpoint.
+
+@table @code
+@item condition @var{bnum} @var{expression}
+@kindex condition
Specify @var{expression} as the break condition for breakpoint or
watchpoint number @var{bnum}. From now on, this breakpoint will stop
-the program only if the value of @var{expression} is true (nonzero, in
+your program only if the value of @var{expression} is true (nonzero, in
C). When you use @code{condition}, _GDBN__ checks @var{expression}
immediately for syntactic correctness, and to determine whether symbols
-in it have referents in the context of your breakpoint. _GDBN__ does
+in it have referents in the context of your breakpoint.
+@c FIXME so what does GDB do if there is no referent? Moreover, what
+@c about watchpoints?
+_GDBN__ does
not actually evaluate @var{expression} at the time the @code{condition}
command is given, however. @xref{Expressions}.
useful that there is a special way to do it, using the @dfn{ignore
count} of the breakpoint. Every breakpoint has an ignore count, which
is an integer. Most of the time, the ignore count is zero, and
-therefore has no effect. But if the program reaches a breakpoint whose
+therefore has no effect. But if your program reaches a breakpoint whose
ignore count is positive, then instead of stopping, it just decrements
the ignore count by one and continues. As a result, if the ignore count
value is @var{n}, the breakpoint will not stop the next @var{n} times it
@itemx c @var{count}
@itemx fg @var{count}
@kindex continue @var{count}
-Continue execution of the program, setting the ignore count of the
-breakpoint that the program stopped at to @var{count} minus one.
-Thus, the program will not stop at this breakpoint until the
+Continue execution of your program, setting the ignore count of the
+breakpoint where your program stopped to @var{count} minus one.
+Thus, your program will not stop at this breakpoint until the
@var{count}'th time it is reached.
-An argument to this command is meaningful only when the program stopped
+An argument to this command is meaningful only when your program stopped
due to a breakpoint. At other times, the argument to @code{continue} is
ignored.
is not checked. Once the ignore count reaches zero, the condition will
be checked.
-You could achieve the effect of the ignore count with a
-condition such as _0__@w{@samp{$foo-- <= 0}}_1__ using a debugger convenience
-variable that is decremented each time. @xref{Convenience Vars}.
+You could achieve the effect of the ignore count with a condition such
+as _0__@w{@samp{$foo-- <= 0}}_1__ using a debugger convenience
+variable that is decremented each time. @xref{Convenience Vars,
+,Convenience Variables}.@refill
@node Break Commands, Breakpoint Menus, Conditions, Breakpoints
@subsection Breakpoint Command Lists
@cindex breakpoint commands
You can give any breakpoint (or watchpoint) a series of commands to
-execute when the program stops due to that breakpoint. For example, you
+execute when your program stops due to that breakpoint. For example, you
might want to print the values of certain expressions, or enable other
breakpoints.
themselves appear on the following lines. Type a line containing just
@code{end} to terminate the commands.
-To remove all commands from a breakpoint, type @code{commands} followed
-immediately by @code{end}; that is, give no commands.
+To remove all commands from a breakpoint, type @code{commands} and
+follow it immediately with @code{end}; that is, give no commands.
With no @var{bnum} argument, @code{commands} refers to the last
breakpoint or watchpoint set (not to the breakpoint most recently
Pressing @key{RET} as a means of repeating the last _GDBN__ command is
disabled within a @var{command-list}.
-You can use breakpoint commands to start the program up again. Simply
+You can use breakpoint commands to start your program up again. Simply
use the @code{continue} command, or @code{step}, or any other command
that resumes execution. Subsequent commands in the command list are
ignored.
stopping at a breakpoint is not printed. This may be desirable for
breakpoints that are to print a specific message and then continue.
If the remaining commands too print nothing, you will see no sign that
-the breakpoint was reached at all. @code{silent} is meaningful only
+the breakpoint was reached at all. @code{silent} is meaningful only
at the beginning of a breakpoint command list.
-The commands @code{echo} and @code{output} that allow you to print precisely
-controlled output are often useful in silent breakpoints. @xref{Output}.
+The commands @code{echo} and @code{output} that allow you to print
+precisely controlled output are often useful in silent breakpoints.
+@xref{Output, ,Commands for Controlled Output}.
For example, here is how you could use breakpoint commands to print the
value of @code{x} at entry to @code{foo} whenever @code{x} is positive.
of code, give it a condition to detect the case in which something
erroneous has been done, and give it commands to assign correct values
to any variables that need them. End with the @code{continue} command
-so that the program does not stop, and start with the @code{silent}
+so that your program does not stop, and start with the @code{silent}
command so that no output is produced. Here is an example:
@example
under Unix appears when your program uses raw mode for the terminal.
_GDBN__ switches back to its own terminal modes (not raw) before executing
commands, and then must switch back to raw mode when your program is
-continued. This causes any pending terminal input to be lost.
+continued. This causes any pending terminal input to be lost.
@c FIXME: revisit below when GNU sys avail.
@c In the GNU system, this will be fixed by changing the behavior of
@c terminal modes.
@end example
@noindent
-specifies a condition expression (@xref{Expressions}) that will change
-@code{x} as needed, then always have the value zero so the program will
+specifies a condition expression (@pxref{Expressions}) that will change
+@code{x} as needed, then always have the value zero so your program will
not stop. No input is lost here, because _GDBN__ evaluates break
-conditions without changing the terminal modes. When you want to have
+conditions without changing the terminal modes. When you want to have
nontrivial conditions for performing the side effects, the operators
@samp{&&}, @samp{||} and @samp{?@dots{}:} may be useful.
@node Breakpoint Menus, Error in Breakpoints, Break Commands, Breakpoints
@subsection Breakpoint Menus
-@cindex C++ overloading
+@cindex overloading
@cindex symbol overloading
Some programming languages (notably C++) permit a single function name
@code{break} command without setting any new breakpoints.
For example, the following session excerpt shows an attempt to set a
-breakpoint at the overloaded symbol @code{String::after}.
+breakpoint at the overloaded symbol @code{String::after}.
We choose three particular definitions of that function name:
@example
Breakpoint 3 at 0xafcc: file String.cc, line 846.
Multiple breakpoints were set.
Use the "delete" command to delete unwanted breakpoints.
-(_GDBP__)
+(_GDBP__)
@end example
@node Error in Breakpoints, , Breakpoint Menus, Breakpoints
@subsection ``Cannot Insert Breakpoints''
-@c FIXME: "cannot insert breakpoints" error, v unclear.
+@c FIXME: "cannot insert breakpoints" error, v unclear.
+@c some light may be shed by looking at instances of
+@c ONE_PROCESS_WRITETEXT. But error seems possible otherwise
+@c too. pesch, 20sep91
Under some operating systems, breakpoints cannot be used in a program if
any other process is running that program. In this situation,
attempting to run or continue a program with a breakpoint causes _GDBN__
Remove or disable the breakpoints, then continue.
@item
-Suspend _GDBN__, and copy the file containing the program to a new name.
+Suspend _GDBN__, and copy the file containing your program to a new name.
Resume _GDBN__ and use the @code{exec-file} command to specify that _GDBN__
-should run the program under that name. Then start the program again.
+should run your program under that name. Then start your program again.
@c FIXME: RMS commented here "Show example". Maybe when someone
@c explains the first FIXME: in this section...
@item
-Relink the program so that the text segment is nonsharable, using the
+Relink your program so that the text segment is nonsharable, using the
linker option @samp{-N}. The operating system limitation may not apply
to nonsharable executables.
@end enumerate
@cindex continuing
@cindex resuming execution
@dfn{Continuing} means resuming program execution until your program
-completes normally. In contrast, @dfn{stepping} means resuming program
-execution for a very limited time: one line of source code, or one
-machine instruction. Either when continuing or when stepping, the
-program may stop even sooner, due to a breakpoint or to a signal. (If
-due to a signal, you may want to use @code{handle}, or use @samp{signal
-0} to resume execution; @pxref{Signals}.)
+completes normally. In contrast, @dfn{stepping} means executing just
+one more ``step'' of your program, where ``step'' may mean either one
+line of source code, or one machine instruction (depending on what
+particular command you use). Either when continuing
+or when stepping, your program may stop even sooner, due to a breakpoint
+or to a signal. (If due to a signal, you may want to use @code{handle},
+or use @samp{signal 0} to resume execution. @xref{Signals}.)@refill
@table @code
@item continue @r{[}@var{ignore-count}@r{]}
@kindex continue
-Resume program execution, at the address where the program last stopped;
+Resume program execution, at the address where your program last stopped;
any breakpoints set at that address are bypassed. The optional argument
@var{ignore-count} allows you to specify a further number of times to
ignore a breakpoint at this location; its effect is like that of
-@code{ignore} (@pxref{Conditions}).
+@code{ignore} (@pxref{Conditions, ,Break Conditions}).
To resume execution at a different place, you can use @code{return}
-(@pxref{Returning}) to go back to the calling function; or @code{jump}
-(@pxref{Jumping}) to go to an arbitrary location in your program.
+(@pxref{Returning, ,Returning from a Function}) to go back to the
+calling function; or @code{jump} (@pxref{Jumping, ,Continuing at a
+Different Address}) to go to an arbitrary location in your program.@refill
@end table
A typical technique for using stepping is to set a breakpoint
-(@pxref{Breakpoints}) at the beginning of the function or the section of
-the program in which a problem is believed to lie, run the program until
-it stops at that breakpoint, and then step through the suspect area,
-examining the variables that are interesting, until you see the problem
-happen.
+(@pxref{Breakpoints, ,Breakpoints Watchpoints and Exceptions}) at the
+beginning of the function or the section of your program where a
+problem is believed to lie, run your program until it stops at that
+breakpoint, and then step through the suspect area, examining the
+variables that are interesting, until you see the problem happen.
@table @code
@item step
@kindex step
@kindex s
-Continue running the program until control reaches a different source
+Continue running your program until control reaches a different source
line, then stop it and return control to _GDBN__. This command is
abbreviated @code{s}.
Continue running until just after function in the selected stack frame
returns. Print the returned value (if any).
-Contrast this with the @code{return} command (@pxref{Returning}).
+Contrast this with the @code{return} command (@pxref{Returning,
+,Returning from a Function}).@refill
@item until
@kindex until
than the address of the jump.
This means that when you reach the end of a loop after single stepping
-though it, @code{until} will cause the program to continue execution
+though it, @code{until} will cause your program to continue execution
until the loop is exited. In contrast, a @code{next} command at the end
of a loop will simply step back to the beginning of the loop, which
would force you to step through the next iteration.
-@code{until} always stops the program if it attempts to exit the current
+@code{until} always stops your program if it attempts to exit the current
stack frame.
@code{until} may produce somewhat counterintuitive results if the order
@example
(_GDBP__) f
#0 main (argc=4, argv=0xf7fffae8) at m4.c:206
-206 expand_input();
+206 expand_input();
(_GDBP__) until
-195 for ( ; argc > 0; NEXTARG) @{
+195 for ( ; argc > 0; NEXTARG) @{
@end example
This happened because, for execution efficiency, the compiler had
@item until @var{location}
@item u @var{location}
-Continue running the program until either the specified location is
-reached, or the current stack frame returns. @var{location}
-is any of the forms of argument acceptable to @code{break} (@pxref{Set
-Breaks}). This form of the command uses breakpoints, and hence is
-quicker than @code{until} without an argument.
+Continue running your program until either the specified location is
+reached, or the current stack frame returns. @var{location} is any of
+the forms of argument acceptable to @code{break} (@pxref{Set Breaks,
+,Setting Breakpoints}). This form of the command uses breakpoints,
+and hence is quicker than @code{until} without an argument.@refill
@item stepi
@itemx si
It is often useful to do @samp{display/i $pc} when stepping by machine
instructions. This will cause the next instruction to be executed to
-be displayed automatically at each stop. @xref{Auto Display}.
+be displayed automatically at each stop. @xref{Auto Display,
+,Automatic Display}.
An argument is a repeat count, as in @code{step}.
signal a program gets when you type an interrupt (often @kbd{C-c});
@code{SIGSEGV} is the signal a program gets from referencing a place in
memory far away from all the areas in use; @code{SIGALRM} occurs when
-the alarm clock timer goes off (which happens only if the program has
+the alarm clock timer goes off (which happens only if your program has
requested an alarm).
@cindex fatal signals
Some signals, including @code{SIGALRM}, are a normal part of the
-functioning of the program. Others, such as @code{SIGSEGV}, indicate
-errors; these signals are @dfn{fatal} (kill the program immediately) if the
+functioning of your program. Others, such as @code{SIGSEGV}, indicate
+errors; these signals are @dfn{fatal} (kill your program immediately) if the
program has not specified in advance some other way to handle the signal.
-@code{SIGINT} does not indicate an error in the program, but it is normally
+@code{SIGINT} does not indicate an error in your program, but it is normally
fatal so it can carry out the purpose of the interrupt: to kill the program.
-_GDBN__ has the ability to detect any occurrence of a signal in the program
-running under _GDBN__'s control. You can tell _GDBN__ in advance what to do for
-each kind of signal.
+_GDBN__ has the ability to detect any occurrence of a signal in your
+program. You can tell _GDBN__ in advance what to do for each kind of
+signal.
@cindex handling signals
Normally, _GDBN__ is set up to ignore non-erroneous signals like @code{SIGALRM}
-(so as not to interfere with their role in the functioning of the program)
-but to stop the program immediately whenever an error signal happens.
+(so as not to interfere with their role in the functioning of your program)
+but to stop your program immediately whenever an error signal happens.
You can change these settings with the @code{handle} command.
@table @code
@table @code
@item nostop
-_GDBN__ should not stop the program when this signal happens. It may
+_GDBN__ should not stop your program when this signal happens. It may
still print a message telling you that the signal has come in.
@item stop
-_GDBN__ should stop the program when this signal happens. This implies
+_GDBN__ should stop your program when this signal happens. This implies
the @code{print} keyword as well.
@item print
implies the @code{nostop} keyword as well.
@item pass
-_GDBN__ should allow the program to see this signal; the program will be
+_GDBN__ should allow your program to see this signal; your program will be
able to handle the signal, or may be terminated if the signal is fatal
and not handled.
@item nopass
-_GDBN__ should not allow the program to see this signal.
+_GDBN__ should not allow your program to see this signal.
@end table
@c @end group
-When a signal has been set to stop the program, the program cannot see the
+When a signal has been set to stop your program, your program cannot see the
signal until you continue. It will see the signal then, if @code{pass} is
in effect for the signal in question @i{at that time}. In other words,
after _GDBN__ reports a signal, you can use the @code{handle} command with
@code{pass} or @code{nopass} to control whether that signal will be seen by
-the program when you later continue it.
+your program when you later continue it.
-You can also use the @code{signal} command to prevent the program from
+You can also use the @code{signal} command to prevent your program from
seeing a signal, or cause it to see a signal it normally would not see,
-or to give it any signal at any time. For example, if the program stopped
+or to give it any signal at any time. For example, if your program stopped
due to some sort of memory reference error, you might store correct
values into the erroneous variables and continue, hoping to see more
-execution; but the program would probably terminate immediately as
-a result of the fatal signal once it sees the signal. To prevent this,
-you can continue with @samp{signal 0}. @xref{Signaling}.
+execution; but your program would probably terminate immediately as
+a result of the fatal signal once it saw the signal. To prevent this,
+you can continue with @samp{signal 0}. @xref{Signaling, ,Giving your
+Program a Signal}.
@node Stack, Source, Stopping, Top
@chapter Examining the Stack
@cindex call stack
Each time your program performs a function call, the information about
-where in the program the call was made from is saved in a block of data
+where in your program the call was made from is saved in a block of data
called a @dfn{stack frame}. The frame also contains the arguments of the
call and the local variables of the function that was called. All the
stack frames are allocated in a region of memory called the @dfn{call
@cindex selected frame
One of the stack frames is @dfn{selected} by _GDBN__ and many _GDBN__ commands
refer implicitly to the selected frame. In particular, whenever you ask
-_GDBN__ for the value of a variable in the program, the value is found in the
+_GDBN__ for the value of a variable in your program, the value is found in the
selected frame. There are special _GDBN__ commands to select whichever frame
you are interested in.
-When the program stops, _GDBN__ automatically selects the currently executing
+When your program stops, _GDBN__ automatically selects the currently executing
frame and describes it briefly as the @code{frame} command does
-(@pxref{Frame Info, Info}).
+(@pxref{Frame Info, ,Information About a Frame}).
@menu
-* Frames:: Stack Frames
-* Backtrace:: Backtraces
-* Selection:: Selecting a Frame
-* Frame Info:: Information on a Frame
+* Frames:: Stack Frames
+* Backtrace:: Backtraces
+* Selection:: Selecting a Frame
+* Frame Info:: Information on a Frame
@end menu
@node Frames, Backtrace, Stack, Stack
@node Backtrace, Selection, Frames, Stack
@section Backtraces
-A backtrace is a summary of how the program got where it is. It shows one
+A backtrace is a summary of how your program got where it is. It shows one
line per frame, for many frames, starting with the currently executing
frame (frame zero), followed by its caller (frame one), and on up the
stack.
@smallexample
@group
-#0 m4_traceon (obs=0x24eb0, argc=1, argv=0x2b8c8) at builtin.c:993
+#0 m4_traceon (obs=0x24eb0, argc=1, argv=0x2b8c8)
+ at builtin.c:993
#1 0x6e38 in expand_macro (sym=0x2b600) at macro.c:242
#2 0x6840 in expand_token (obs=0x0, t=177664, td=0xf7fffb08)
at macro.c:71
@end smallexample
@noindent
-The display for frame zero doesn't begin with a program counter
-value, indicating that the program has stopped at the beginning of the
+The display for frame zero does not begin with a program counter
+value, indicating that your program has stopped at the beginning of the
code for line @code{993} of @code{builtin.c}.
@node Selection, Frame Info, Backtrace, Stack
@section Selecting a Frame
-Most commands for examining the stack and other data in the program work on
+Most commands for examining the stack and other data in your program work on
whichever stack frame is selected at the moment. Here are the commands for
selecting a stack frame; all of them finish by printing a brief description
of the stack frame just selected.
Select the frame at address @var{addr}. This is useful mainly if the
chaining of stack frames has been damaged by a bug, making it
impossible for _GDBN__ to assign numbers properly to all frames. In
-addition, this can be useful when the program has multiple stacks and
+addition, this can be useful when your program has multiple stacks and
switches between them.
-_if_(_SPARC__)
+_if__(_SPARC__)
On the SPARC architecture, @code{frame} needs two addresses to
-select an arbitrary frame: a frame pointer and a stack pointer.
+select an arbitrary frame: a frame pointer and a stack pointer.
@c note to future updaters: this is conditioned on a flag
@c FRAME_SPECIFICATION_DYADIC in the tm-*.h files, currently only used
@c by SPARC, hence the specific attribution. Generalize or list all
@c possibilities if more supported machines start doing this.
-_fi_(_SPARC__)
+_fi__(_SPARC__)
@item up @var{n}
@kindex up
example:
@smallexample
+@group
(_GDBP__) up
-#1 0x22f0 in main (argc=1, argv=0xf7fffbf4, env=0xf7fffbfc) at env.c:10
+#1 0x22f0 in main (argc=1, argv=0xf7fffbf4, env=0xf7fffbfc)
+ at env.c:10
10 read_input_file (argv[i]);
+@end group
@end smallexample
-After such a printout, the @code{list} command with no arguments will print
-ten lines centered on the point of execution in the frame. @xref{List}.
+After such a printout, the @code{list} command with no arguments will
+print ten lines centered on the point of execution in the frame.
+@xref{List, ,Printing Source Lines}.
@table @code
@item up-silently @var{n}
respectively; they differ in that they do their work silently, without
causing display of the new frame. They are intended primarily for use
in _GDBN__ command scripts, where the output might be unnecessary and
-distracting.
+distracting.
@end table
@table @code
@item frame
@itemx f
-When used without any argument, this command does not change which frame
-is selected, but prints a brief description of the currently
+When used without any argument, this command does not change which
+frame is selected, but prints a brief description of the currently
selected stack frame. It can be abbreviated @code{f}. With an
-argument, this command is used to select a stack frame (@pxref{Selection}).
+argument, this command is used to select a stack frame
+(@pxref{Selection, ,Selecting a Frame}).
@item info frame
-@kindex info frame
@itemx info f
+@kindex info frame
@kindex info f
This command prints a verbose description of the selected stack frame,
including the address of the frame, the addresses of the next frame down
-(called by this frame) and the next frame up (caller of this frame),
+(called by this frame) and the next frame up (caller of this frame), the
+language that the source code corresponding to this frame was written in,
the address of the frame's arguments, the program counter saved in it
(the address of execution in the caller frame), and which registers
were saved in the frame. The verbose description is useful when
current stack frame at the current point of execution. To see other
exception handlers, visit the associated frame (using the @code{up},
@code{down}, or @code{frame} commands); then type @code{info catch}.
-@xref{Exception Handling}.
+@xref{Exception Handling, ,Breakpoints and Exceptions}.@refill
@end table
@node Source, Data, Stack, Top
_GDBN__ can print parts of your program's source, since the debugging
information recorded in your program tells _GDBN__ what source files
-were used to built it. When your program stops, _GDBN__ spontaneously
+were used to build it. When your program stops, _GDBN__ spontaneously
prints the line where it stopped. Likewise, when you select a stack
-frame (@pxref{Selection}), _GDBN__ prints the line where execution in
-that frame has stopped. You can print other portions of source files by
-explicit command.
+frame (@pxref{Selection, ,Selecting a Frame}), _GDBN__ prints the line
+where execution in that frame has stopped. You can print other
+portions of source files by explicit command.@refill
If you use _GDBN__ through its GNU Emacs interface, you may prefer to
-use Emacs facilities to view source; @pxref{Emacs}.
+use Emacs facilities to view source; @pxref{Emacs, ,Using _GDBN__
+under GNU Emacs}.@refill
@menu
-* List:: Printing Source Lines
-* Search:: Searching Source Files
-* Source Path:: Specifying Source Directories
-* Machine Code:: Source and Machine Code
+* List:: Printing Source Lines
+* Search:: Searching Source Files
+* Source Path:: Specifying Source Directories
+* Machine Code:: Source and Machine Code
@end menu
@node List, Search, Source, Source
@table @code
@item list @var{linenum}
-Print ten lines centered around line number @var{linenum} in the
+Print lines centered around line number @var{linenum} in the
current source file.
@item list @var{function}
-Print ten lines centered around the beginning of function
+Print lines centered around the beginning of function
@var{function}.
@item list
-Print ten more lines. If the last lines printed were printed with a
-@code{list} command, this prints ten lines following the last lines
+Print more lines. If the last lines printed were printed with a
+@code{list} command, this prints lines following the last lines
printed; however, if the last line printed was a solitary line printed
-as part of displaying a stack frame (@pxref{Stack}), this prints ten
-lines centered around that line.
+as part of displaying a stack frame (@pxref{Stack, ,Examining the
+Stack}), this prints lines centered around that line.@refill
@item list -
-Print ten lines just before the lines last printed.
+Print lines just before the lines last printed.
+@end table
+
+By default, _GDBN__ prints ten source lines with any of these forms of
+the @code{list} command. You can change this using @code{set listsize}:
+
+@table @code
+@item set listsize @var{count}
+@kindex set listsize
+Make the @code{list} command display @var{count} source lines (unless
+the @code{list} argument explicitly specifies some other number).
+
+@item show listsize
+@kindex show listsize
+Display the number of lines that @code{list} will currently display by
+default.
@end table
Repeating a @code{list} command with @key{RET} discards the argument,
@table @code
@item list @var{linespec}
-Print ten lines centered around the line specified by @var{linespec}.
+Print lines centered around the line specified by @var{linespec}.
@item list @var{first},@var{last}
Print lines from @var{first} to @var{last}. Both arguments are
linespecs.
@item list ,@var{last}
-Print ten lines ending with @var{last}.
+Print lines ending with @var{last}.
@item list @var{first},
-Print ten lines starting with @var{first}.
+Print lines starting with @var{first}.
@item list +
-Print ten lines just after the lines last printed.
+Print lines just after the lines last printed.
@item list -
-Print ten lines just before the lines last printed.
+Print lines just before the lines last printed.
@item list
As described in the preceding table.
the current working directory, unless it happens to be in the source
path.
-If _GDBN__ can't find a source file in the source path, and the object
+If _GDBN__ cannot find a source file in the source path, and the object
program records a directory, _GDBN__ tries that directory too. If the
source path is empty, and there is no record of the compilation
directory, _GDBN__ will, as a last resort, look in the current
Add directory @var{dirname} to the front of the source path. Several
directory names may be given to this command, separated by @samp{:} or
whitespace. You may specify a directory that is already in the source
-path; this moves it forward, so it will be searched sooner.
+path; this moves it forward, so it will be searched sooner.
You can use the string @samp{$cdir} to refer to the compilation
directory (if one is recorded), and @samp{$cwd} to refer to the current
Reset the source path to empty again. This requires confirmation.
@c RET-repeat for @code{directory} is explicitly disabled, but since
-@c repeating it would be a no-op we don't say that. (thanks to RMS)
+@c repeating it would be a no-op we do not say that. (thanks to RMS)
@item show directories
@kindex show directories
@kindex info line
Print the starting and ending addresses of the compiled code for
source line @var{linespec}. You can specify source lines in any of the
-ways understood by the @code{list} command (@pxref{List}).
+ways understood by the @code{list} command (@pxref{List, ,Printing Source Lines}).
@end table
For example, we can use @code{info line} to inquire on where the object
Line 926 of "builtin.c" starts at pc 0x63e4 and ends at 0x6404.
@end smallexample
-@kindex $_
-After @code{info line}, the default address for the @code{x}
-command is changed to the starting address of the line, so that
-@samp{x/i} is sufficient to begin examining the machine code
-(@pxref{Memory}). Also, this address is saved as the value of the
-convenience variable @code{$_} (@pxref{Convenience Vars}).
+@cindex @code{$_} and @code{info line}
+After @code{info line}, the default address for the @code{x} command
+is changed to the starting address of the line, so that @samp{x/i} is
+sufficient to begin examining the machine code (@pxref{Memory,
+,Examining Memory}). Also, this address is saved as the value of the
+convenience variable @code{$_} (@pxref{Convenience Vars, ,Convenience
+Variables}).
@table @code
@kindex disassemble
argument to this command is a program counter value; the function
surrounding this value will be dumped. Two arguments (separated by one
or more spaces) specify a range of addresses (first inclusive, second
-exclusive) to be dumped.
+exclusive) to be dumped.
@end table
We can use @code{disassemble} to inspect the object code
@smallexample
(_GDBP__) disas 0x63e4 0x6404
Dump of assembler code from 0x63e4 to 0x6404:
-0x63e4 <builtin_init+5340>: ble 0x63f8 <builtin_init+5360>
-0x63e8 <builtin_init+5344>: sethi %hi(0x4c00), %o0
-0x63ec <builtin_init+5348>: ld [%i1+4], %o0
-0x63f0 <builtin_init+5352>: b 0x63fc <builtin_init+5364>
-0x63f4 <builtin_init+5356>: ld [%o0+4], %o0
-0x63f8 <builtin_init+5360>: or %o0, 0x1a4, %o0
-0x63fc <builtin_init+5364>: call 0x9288 <path_search>
-0x6400 <builtin_init+5368>: nop
+0x63e4 <builtin_init+5340>: ble 0x63f8 <builtin_init+5360>
+0x63e8 <builtin_init+5344>: sethi %hi(0x4c00), %o0
+0x63ec <builtin_init+5348>: ld [%i1+4], %o0
+0x63f0 <builtin_init+5352>: b 0x63fc <builtin_init+5364>
+0x63f4 <builtin_init+5356>: ld [%o0+4], %o0
+0x63f8 <builtin_init+5360>: or %o0, 0x1a4, %o0
+0x63fc <builtin_init+5364>:
call 0x9288 <path_search>
+0x6400 <builtin_init+5368>: nop
End of assembler dump.
-(_GDBP__)
+(_GDBP__)
@end smallexample
-@node Data, Symbols, Source, Top
+@node Data, Languages, Source, Top
@chapter Examining Data
@cindex printing data
@cindex examining data
@kindex print
@kindex inspect
-@c "inspect" isn't quite a synonym if you're using Epoch, which we don't
-@c document because it's nonstandard... Under Epoch it displays in a
+@c "inspect" isn't quite a synonym if you are using Epoch, which we do not
+@c document because it is nonstandard... Under Epoch it displays in a
@c different window or something like that.
The usual way to examine data in your program is with the @code{print}
command (abbreviated @code{p}), or its synonym @code{inspect}. It
-evaluates and prints the value of any valid expression of the language
-the program is written in (for now, C or C++). You type
+evaluates and prints the value of an expression of the language your
+program is written in (@pxref{Languages}).
-@example
-print @var{exp}
-@end example
-
-@noindent
-where @var{exp} is any valid expression (in the source language), and
+@table @code
+@item print @var{exp}
+@itemx print /@var{f} @var{exp}
+@var{exp} is an expression (in the source language). By default
the value of @var{exp} is printed in a format appropriate to its data
-type.
+type; you can choose a different format by specifying @samp{/@var{f}},
+where @var{f} is a letter specifying the format; @pxref{Output formats}.
+
+@item print
+@itemx print /@var{f}
+If you omit @var{exp}, _GDBN__ displays the last value again (from the
+@dfn{value history}; @pxref{Value History}). This allows you to
+conveniently inspect the same value in an alternative format.
+@end table
A more low-level way of examining data is with the @code{x} command.
It examines data in memory at a specified address and prints it in a
-specified format. @xref{Memory}.
+specified format. @xref{Memory, ,Examining Memory}.
+
+If you are interested in information about types, or about how the fields
+of a struct or class are declared, use the @code{ptype @var{exp}}
+command rather than @code{print}. @xref{Symbols}.
@menu
-* Expressions:: Expressions
-* Variables:: Program Variables
-* Arrays:: Artificial Arrays
-* Output formats:: Output formats
-* Memory:: Examining Memory
-* Auto Display:: Automatic Display
-* Print Settings:: Print Settings
-* Value History:: Value History
-* Convenience Vars:: Convenience Variables
-* Registers:: Registers
-* Floating Point Hardware:: Floating Point Hardware
+* Expressions:: Expressions
+* Variables:: Program Variables
+* Arrays:: Artificial Arrays
+* Output formats:: Output formats
+* Memory:: Examining Memory
+* Auto Display:: Automatic Display
+* Print Settings:: Print Settings
+* Value History:: Value History
+* Convenience Vars:: Convenience Variables
+* Registers:: Registers
+* Floating Point Hardware:: Floating Point Hardware
@end menu
@node Expressions, Variables, Data, Data
by the programming language you are using is legal in an expression in
_GDBN__. This includes conditional expressions, function calls, casts
and string constants. It unfortunately does not include symbols defined
-by preprocessor @code{#define} commands, or C++ expressions involving
-@samp{::}, the name resolution operator.
-@c FIXME: actually C++ a::b works except in obscure circumstances where it
-@c FIXME...can conflict with GDB's own name scope resolution.
+by preprocessor @code{#define} commands.
+
+Because C is so widespread, most of the expressions shown in examples in
+this manual are in C. @xref{Languages,, Using _GDBN__ with Different
+Languages}, for information on how to use expressions in other
+languages.
+
+In this section, we discuss operators that you can use in _GDBN__
+expressions regardless of your programming language.
Casts are supported in all languages, not just in C, because it is so
useful to cast a number into a pointer so as to examine a structure
at that address in memory.
+@c FIXME: casts supported---Mod2 true?
-_GDBN__ supports three kinds of operator in addition to those of programming
+_GDBN__ supports these operators in addition to those of programming
languages:
@table @code
in your program.
Variables in expressions are understood in the selected stack frame
-(@pxref{Selection}); they must either be global (or static) or be visible
-according to the scope rules of the programming language from the point of
-execution in that frame. This means that in the function
+(@pxref{Selection, ,Selecting a Frame}); they must either be global
+(or static) or be visible according to the scope rules of the
+programming language from the point of execution in that frame. This
+means that in the function
@example
foo (a)
@end example
@noindent
-the variable @code{a} is usable whenever the program is executing
+the variable @code{a} is usable whenever your program is executing
within the function @code{foo}, but the variable @code{b} is visible
-only while the program is executing inside the block in which @code{b}
+only while your program is executing inside the block in which @code{b}
is declared.
@cindex variable name conflict
specify a variable in a particular file, using the colon-colon notation:
@cindex colon-colon
+@iftex
+@c info cannot cope with a :: index entry, but why deprive hard copy readers?
@kindex ::
+@end iftex
@example
@var{file}::@var{variable}
@end example
@noindent
Here @var{file} is the name of the source file whose variable you want.
-@cindex C++ name resolution
+@cindex C++ scope resolution
This use of @samp{::} is very rarely in conflict with the very similar
use of the same notation in C++. _GDBN__ also supports use of the C++
-name resolution operator in _GDBN__ expressions.
+scope resolution operator in _GDBN__ expressions.
@cindex wrong values
@cindex variable values, wrong
@quotation
@emph{Warning:} Occasionally, a local variable may appear to have the
wrong value at certain points in a function---just after entry to the
-function, and just before exit. You may see this problem when you're
+function, and just before exit. You may see this problem when you are
stepping by machine instructions. This is because on most machines, it
takes more than one instruction to set up a stack frame (including local
-variable definitions); if you're stepping by machine instructions,
+variable definitions); if you are stepping by machine instructions,
variables may appear to have the wrong values until the stack frame is
completely built. On function exit, it usually also takes more than one
machine instruction to destroy a stack frame; after you begin stepping
Sometimes the artificial array mechanism isn't quite enough; in
moderately complex data structures, the elements of interest may not
-actually be adjacent---for example, if you're interested in the values
-of pointers in an array. One useful work-around in this situation is to
-use a convenience variable (@pxref{Convenience Vars}) as a counter in an
-expression that prints the first interesting value, and then repeat that
-expression via @key{RET}. For instance, suppose you have an array
-@code{dtab} of pointers to structures, and you're interested in the
-values of a field @code{fv} in each structure. Here's an example of
-what you might type:
+actually be adjacent---for example, if you are interested in the
+values of pointers in an array. One useful work-around in this
+situation is to use a convenience variable (@pxref{Convenience Vars,
+,Convenience Variables}) as a counter in an expression that prints the
+first interesting value, and then repeat that expression via
+@key{RET}. For instance, suppose you have an array @code{dtab} of
+pointers to structures, and you are interested in the values of a
+field @code{fv} in each structure. Here's an example of what you
+might type:
@example
set $i = 0
p dtab[$i++]->fv
@cindex examining memory
@table @code
@kindex x
-@item x/@var{nfu} @var{expr}
-The command @code{x} (for `examine') can be used to examine memory
-without being constrained by your program's data types. You can specify
-the unit size @var{u} of memory to inspect, and a repeat count @var{n} of how
-many of those units to display. @code{x} understands the formats
-@var{f} used by @code{print}; two additional formats, @samp{s} (string)
-and @samp{i} (machine instruction) can be used without specifying a unit
-size.
+@item x/@var{nfu} @var{addr}
+@itemx x @var{addr}
+@itemx x
+You can use the command @code{x} (for `examine') to examine memory in
+any of several formats, independently of your program's data types.
+@var{n}, @var{f}, and @var{u} are all optional parameters to specify how
+much memory to display, and how to format it; @var{addr} is an
+expression giving the address where you want to start displaying memory.
+If you use defaults for @var{nfu}, you need not type the slash @samp{/}.
+Several commands set convenient defaults for @var{addr}.
@end table
-For example, @samp{x/3uh 0x54320} is a request to display three halfwords
-(@code{h}) of memory, formatted as unsigned decimal integers (@samp{u}),
-starting at address @code{0x54320}. @samp{x/4xw $sp} prints the four
-words (@samp{w}) of memory above the stack pointer (here, @samp{$sp};
-@pxref{Registers}) in hexadecimal (@samp{x}).
-
-Since the letters indicating unit sizes are all distinct from the
-letters specifying output formats, you don't have to remember whether
-unit size or format comes first; either order will work. The output
-specifications @samp{4xw} and @samp{4wx} mean exactly the same thing.
-
-After the format specification, you supply an expression for the address
-where _GDBN__ is to begin reading from memory. The expression need not
-have a pointer value (though it may); it is always interpreted as an
-integer address of a byte of memory. @xref{Expressions} for more
-information on expressions.
+@var{n}, the repeat count, is a decimal integer; the default is 1. It
+specifies how much memory (counting by units @var{u}) to display.
+@c This really is **decimal**; unaffected by 'set radix' as of GDB
+@c 4.1.2.
-These are the memory units @var{u} you can specify with the @code{x}
-command:
+@var{f}, the display format, is one of the formats used by @code{print},
+or @samp{s} (null-terminated string) or @samp{i} (machine instruction).
+The default is @samp{x} (hexadecimal) initially, or the format from the
+last time you used either @code{x} or @code{print}.
+@var{u}, the unit size, is any of
@table @code
@item b
-Examine individual bytes.
-
+Bytes.
@item h
-Examine halfwords (two bytes each).
-
+Halfwords (two bytes).
@item w
-Examine words (four bytes each).
-
-@cindex word
-Many assemblers and cpu designers still use `word' for a 16-bit quantity,
-as a holdover from specific predecessor machines of the 1970's that really
-did use two-byte words. But more generally the term `word' has always
-referred to the size of quantity that a machine normally operates on and
-stores in its registers. This is 32 bits for all the machines that _GDBN__
-runs on.
-
+Words (four bytes). This is the initial default.
@item g
-Examine giant words (8 bytes).
+Giant words (eight bytes).
@end table
-You can combine these unit specifications with any of the formats
-described for @code{print}. @xref{Output formats}.
-
-@code{x} has two additional output specifications which derive the unit
-size from the data inspected:
-
-@table @code
-@item s
-Print a null-terminated string of characters. Any explicitly specified
-unit size is ignored; instead, the unit is however many bytes it takes
-to reach a null character (including the null character).
-
-@item i
-Print a machine instruction in assembler syntax (or nearly). Any
-specified unit size is ignored; the number of bytes in an instruction
-varies depending on the type of machine, the opcode and the addressing
-modes used. The command @code{disassemble} gives an alternative way of
-inspecting machine instructions. @xref{Machine Code}.
-@end table
-
-If you omit either the format @var{f} or the unit size @var{u}, @code{x}
-will use the same one that was used last. If you don't use any letters
-or digits after the slash, you can omit the slash as well.
-
-You can also omit the address to examine. Then the address used is just
-after the last unit examined. This is why string and instruction
-formats actually compute a unit-size based on the data: so that the next
-string or instruction examined will start in the right place.
-
-When the @code{print} command shows a value that resides in memory,
-@code{print} also sets the default address for the @code{x} command.
-@code{info line} also sets the default for @code{x}, to the address of
-the start of the machine code for the specified line (@pxref{Machine
-Code}), and @code{info breakpoints} sets it to the address of the last
-breakpoint listed (@pxref{Set Breaks}).
-
-When you use @key{RET} to repeat an @code{x} command, the address
-specified previously (if any) is ignored, so that the repeated command
-examines the successive locations in memory rather than the same ones.
-
-You can examine several consecutive units of memory with one command by
-writing a repeat-count after the slash (before the format letters, if
-any). Omitting the repeat count @var{n} displays one unit of the
-appropriate size. The repeat count must be a decimal integer. It has
-the same effect as repeating the @code{x} command @var{n} times except
-that the output may be more compact, with several units per line. For
-example,
-
-@example
-x/10i $pc
-@end example
-
@noindent
-prints ten instructions starting with the one to be executed next in the
-selected frame. After doing this, you could print a further seven
-instructions with
-
-@example
-x/7
-@end example
+Each time you specify a unit size with @code{x}, that size becomes the
+default unit the next time you use @code{x}. (For the @samp{s} and
+@samp{i} formats, the unit size is ignored and is normally not written.)
+
+@var{addr} is the address where you want _GDBN__ to begin displaying
+memory. The expression need not have a pointer value (though it may);
+it is always interpreted as an integer address of a byte of memory.
+@xref{Expressions} for more information on expressions. The default for
+@var{addr} is usually just after the last address examined---but several
+other commands also set the default address: @code{info breakpoints} (to
+the address of the last breakpoint listed), @code{info line} (to the
+starting address of a line), and @code{print} (if you use it to display
+a value from memory).
-@noindent
----where the format and address are allowed to default.
+For example, @samp{x/3uh 0x54320} is a request to display three halfwords
+(@code{h}) of memory, formatted as unsigned decimal integers (@samp{u}),
+starting at address @code{0x54320}. @samp{x/4xw $sp} prints the four
+words (@samp{w}) of memory above the stack pointer (here, @samp{$sp};
+@pxref{Registers}) in hexadecimal (@samp{x}).
-@kindex $_
-@kindex $__
-The addresses and contents printed by the @code{x} command are not put
+Since the letters indicating unit sizes are all distinct from the
+letters specifying output formats, you do not have to remember whether
+unit size or format comes first; either order will work. The output
+specifications @samp{4xw} and @samp{4wx} mean exactly the same thing.
+(However, the count @var{n} must come first; @samp{wx4} will not work.)
+
+Even though the unit size @var{u} is ignored for the formats @samp{s}
+and @samp{i}, you might still want to use a count @var{n}; for example,
+@samp{3i} specifies that you want to see three machine instructions,
+including any operands. The command @code{disassemble} gives an
+alternative way of inspecting machine instructions; @pxref{Machine
+Code}.
+
+All the defaults for the arguments to @code{x} are designed to make it
+easy to continue scanning memory with minimal specifications each time
+you use @code{x}. For example, after you've inspected three machine
+instructions with @samp{x/3i @var{addr}}, you can inspect the next seven
+with just @samp{x/7}. If you use @key{RET} to repeat the @code{x} command,
+the repeat count @var{n} is used again; the other arguments default as
+for successive uses of @code{x}.
+
+@cindex @code{$_}, @code{$__}, and value history
+The addresses and contents printed by the @code{x} command are not saved
in the value history because there is often too much of them and they
would get in the way. Instead, _GDBN__ makes these values available for
subsequent use in expressions as values of the convenience variables
If you find that you want to print the value of an expression frequently
(to see how it changes), you might want to add it to the @dfn{automatic
-display list} so that _GDBN__ will print its value each time the program stops.
+display list} so that _GDBN__ will print its value each time your program stops.
Each expression added to the list is given a number to identify it;
to remove an expression from the list, you specify that number.
The automatic display looks like this:
@item display @var{exp}
@kindex display
Add the expression @var{exp} to the list of expressions to display
-each time the program stops. @xref{Expressions}.
+each time your program stops. @xref{Expressions}.
@code{display} will not repeat if you press @key{RET} again after using it.
@item display/@var{fmt} @var{addr}
For @var{fmt} @samp{i} or @samp{s}, or including a unit-size or a
number of units, add the expression @var{addr} as a memory address to
-be examined each time the program stops. Examining means in effect
-doing @samp{x/@var{fmt} @var{addr}}. @xref{Memory}.
+be examined each time your program stops. Examining means in effect
+doing @samp{x/@var{fmt} @var{addr}}. @xref{Memory, ,Examining Memory}.
@end table
For example, @samp{display/i $pc} can be helpful, to see the machine
@item display
Display the current values of the expressions on the list, just as is
-done when the program stops.
+done when your program stops.
@item info display
@kindex info display
expression is disabled when execution enters a context where one of its
variables is not defined. For example, if you give the command
@code{display last_char} while inside a function with an argument
-@code{last_char}, then this argument will be displayed while the program
+@code{last_char}, then this argument will be displayed while your program
continues to stop inside that function. When it stops elsewhere---where
there is no variable @code{last_char}---display is disabled. The next time
your program stops where @code{last_char} is meaningful, you can enable the
@cindex format options
@cindex print settings
_GDBN__ provides the following ways to control how arrays, structures,
-and symbols are printed.
+and symbols are printed.
@noindent
These settings are useful for debugging programs in any language:
@code{set print address on}:
@smallexample
(_GDBP__) f
-#0 set_quotes (lq=0x34c78 "<<", rq=0x34c88 ">>")
+#0 set_quotes (lq=0x34c78 "<<", rq=0x34c88 ">>")
at input.c:530
-530 if (lquote != def_lquote)
+530 if (lquote != def_lquote)
@end smallexample
@item set print address off
(_GDBP__) set print addr off
(_GDBP__) f
#0 set_quotes (lq="<<", rq=">>") at input.c:530
-530 if (lquote != def_lquote)
+530 if (lquote != def_lquote)
@end example
@item show print address
@item show print array
@kindex show print array
Show whether compressed or pretty format is selected for displaying
-arrays.
+arrays.
@item set print elements @var{number-of-elements}
@kindex set print elements
Show which format _GDBN__ will use to print structures.
@item set print sevenbit-strings on
-Print using only seven-bit characters; if this option is set,
+@kindex set print sevenbit-strings
+Print using only seven-bit characters; if this option is set,
_GDBN__ will display any eight-bit characters (in strings or character
values) using the notation @code{\}@var{nnn}. For example, @kbd{M-a} is
displayed as @code{\341}.
is the default.
@item show print sevenbit-strings
+@kindex show print sevenbit-strings
Show whether or not _GDBN__ will print only seven-bit characters.
@item set print union on
@item show print union
@kindex show print union
Ask _GDBN__ whether or not it will print unions which are contained in
-structures.
+structures.
For example, given the declarations
@smallexample
typedef enum @{Tree, Bug@} Species;
typedef enum @{Big_tree, Acorn, Seedling@} Tree_forms;
-typedef enum @{Caterpillar, Cocoon, Butterfly@} Bug_forms;
+typedef enum @{Caterpillar, Cocoon, Butterfly@}
+ Bug_forms;
struct thing @{
Species it;
These settings are of interest when debugging C++ programs:
@table @code
-@item set print demangle
-@itemx set print demangle on
+@item set print demangle
+@itemx set print demangle on
@kindex set print demangle
Print C++ names in their source form rather than in the mangled form
in which they are passed to the assembler and linker for type-safe linkage.
@kindex show print demangle
Show whether C++ names will be printed in mangled or demangled form.
-@item set print asm-demangle
-@itemx set print asm-demangle on
+@item set print asm-demangle
+@itemx set print asm-demangle on
@kindex set print asm-demangle
Print C++ names in their source form rather than their mangled form, even
in assembler code printouts such as instruction disassemblies.
@kindex show print object
Show whether actual, or declared, object types will be displayed.
-@item set print vtbl
-@itemx set print vtbl on
+@item set print vtbl
+@itemx set print vtbl on
@kindex set print vtbl
Pretty print C++ virtual function tables. The default is off.
@end table
Pressing @key{RET} to repeat @code{show values @var{n}} has exactly the
-same effect as @samp{show values +}.
+same effect as @samp{show values +}.
@node Convenience Vars, Registers, Value History, Data
@section Convenience Variables
@table @code
@item $_
+@kindex $_
The variable @code{$_} is automatically set by the @code{x} command to
-the last address examined (@pxref{Memory}). Other commands which
-provide a default address for @code{x} to examine also set @code{$_}
-to that address; these commands include @code{info line} and @code{info
-breakpoint}.
+the last address examined (@pxref{Memory, ,Examining Memory}). Other
+commands which provide a default address for @code{x} to examine also
+set @code{$_} to that address; these commands include @code{info line}
+and @code{info breakpoint}. The type of @code{$_} is @code{void *}
+except when set by the @code{x} command, in which case it is a pointer
+to the type of @code{$__}.
@item $__
+@kindex $__
The variable @code{$__} is automatically set by the @code{x} command
-to the value found in the last address examined.
+to the value found in the last address examined. Its type is chosen
+to match the format in which the data was printed.
@end table
@node Registers, Floating Point Hardware, Convenience Vars, Data
@section Registers
@cindex registers
-Machine register contents can be referred to in expressions as variables
+You can refer to machine register contents, in expressions, as variables
with names starting with @samp{$}. The names of registers are different
for each machine; use @code{info registers} to see the names used on
-your machine.
+your machine.
@table @code
@item info registers
@kindex info registers
-Print the names and values of all registers (in the selected stack frame).
+Print the names and values of all registers except floating-point
+registers (in the selected stack frame).
+
+@item info all-registers
+@kindex info all-registers
+@cindex floating point registers
+Print the names and values of all registers, including floating-point
+registers.
@item info registers @var{regname}
Print the relativized value of register @var{regname}. @var{regname}
or without the initial @samp{$}.
@end table
-The register names @code{$pc} and @code{$sp} are used on most machines
-for the program counter register and the stack pointer. For example,
+_GDBN__ has four ``standard'' register names that are available (in
+expressions) on most machines---whenever they do not conflict with an
+architecture's canonical mnemonics for registers. The register names
+@code{$pc} and @code{$sp} are used for the program counter register and
+the stack pointer. @code{$fp} is used for a register that contains a
+pointer to the current stack frame, and @code{$ps} is used for a
+register that contains the processor status. For example,
you could print the program counter in hex with
@example
p/x $pc
@end example
@noindent
-or add four to the stack pointer with
+or add four to the stack pointer @footnote{This is a way of removing
+one word from the stack, on machines where stacks grow downward in
+memory (most machines, nowadays). This assumes that the innermost
+stack frame is selected; setting @code{$sp} is not allowed when other
+stack frames are selected. To pop entire frames off the stack,
+regardless of machine architecture, use @code{return};
+@pxref{Returning, ,Returning from a Function}.} with@refill
@example
set $sp += 4
@end example
-@noindent
-The last is a way of removing one word from the stack, on machines where
-stacks grow downward in memory (most machines, nowadays). This assumes
-that the innermost stack frame is selected; setting @code{$sp} is
-not allowed when other stack frames are selected. (To pop entire frames
-off the stack, regardless of machine architecture, use @code{return};
-@pxref{Returning}.)
-
-Often @code{$fp} is used for a register that contains a pointer to the
-current stack frame, and @code{$ps} is sometimes used for a register
-that contains the processor status. These standard register names may
-be available on your machine even though the @code{info registers}
-command shows other names. For example, on the SPARC, @code{info
+Whenever possible, these four standard register names are available on
+your machine even though the machine has different canonical mnemonics,
+so long as there is no conflict. The @code{info registers} command
+shows the canonical names. For example, on the SPARC, @code{info
registers} displays the processor status register as @code{$psr} but you
can also refer to it as @code{$ps}.
prints the data in both formats.
Normally, register values are relative to the selected stack frame
-(@pxref{Selection}). This means that you get the value that the
-register would contain if all stack frames farther in were exited and
-their saved registers restored. In order to see the true contents of
-hardware registers, you must select the innermost frame (with
-@samp{frame 0}).
+(@pxref{Selection, ,Selecting a Frame}). This means that you get the
+value that the register would contain if all stack frames farther in
+were exited and their saved registers restored. In order to see the
+true contents of hardware registers, you must select the innermost
+frame (with @samp{frame 0}).
However, _GDBN__ must deduce where registers are saved, from the machine
code generated by your compiler. If some registers are not saved, or if
floating point chip.
@end table
@c FIXME: this is a cop-out. Try to get examples, explanations. Only
-@c FIXME...supported currently on arm's and 386's. Mark properly with
-@c FIXME... m4 macros to isolate general statements from hardware-dep,
+@c FIXME...supported currently on arm's and 386's. Mark properly with
+@c FIXME... m4 macros to isolate general statements from hardware-dep,
@c FIXME... at that point.
-@node Symbols, Altering, Data, Top
-@chapter Examining the Symbol Table
+@node Languages, Symbols, Data, Top
+@chapter Using _GDBN__ with Different Languages
+@cindex languages
+
+Although programming languages generally have common aspects, they are
+rarely expressed in the same manner. For instance, in ANSI C,
+dereferencing a pointer @code{p} is accomplished by @code{*p}, but in
+Modula-2, it is accomplished by @code{p^}. Values can also be
+represented (and displayed) differently. Hex numbers in C are written
+like @samp{0x1ae}, while in Modula-2 they appear as @samp{1AEH}.
+
+@cindex working language
+Language-specific information is built into _GDBN__ for some languages,
+allowing you to express operations like the above in your program's
+native language, and allowing _GDBN__ to output values in a manner
+consistent with the syntax of your program's native language. The
+language you use to build expressions, called the @dfn{working
+language}, can be selected manually, or _GDBN__ can set it
+automatically.
-The commands described in this section allow you to inquire about the
-symbols (names of variables, functions and types) defined in your
-program. This information is inherent in the text of your program and
-does not change as the program executes. _GDBN__ finds it in your
-program's symbol table, in the file indicated when you started _GDBN__
-(@pxref{File Options}), or by one of the file-management commands
-(@pxref{Files}).
+@menu
+* Setting:: Switching between source languages
+* Show:: Displaying the language
+* Checks:: Type and Range checks
+* Support:: Supported languages
+@end menu
-@table @code
-@item info address @var{symbol}
-@kindex info address
-Describe where the data for @var{symbol} is stored. For a register
-variable, this says which register it is kept in. For a non-register
-local variable, this prints the stack-frame offset at which the variable
-is always stored.
+@node Setting, Show, Languages, Languages
+@section Switching between source languages
-Note the contrast with @samp{print &@var{symbol}}, which does not work
-at all for a register variables, and for a stack local variable prints
-the exact address of the current instantiation of the variable.
+There are two ways to control the working language---either have _GDBN__
+set it automatically, or select it manually yourself. You can use the
+@code{set language} command for either purpose. On startup, _GDBN__
+defaults to setting the language automatically.
-@item whatis @var{exp}
-@kindex whatis
-Print the data type of expression @var{exp}. @var{exp} is not
-actually evaluated, and any side-effecting operations (such as
-assignments or function calls) inside it do not take place.
-@xref{Expressions}.
+@menu
+* Manually:: Setting the working language manually
+* Automatically:: Having _GDBN__ infer the source language
+@end menu
-@item whatis
-Print the data type of @code{$}, the last value in the value history.
+@node Manually, Automatically, Setting, Setting
+@subsection Setting the working language
-@item ptype @var{typename}
-@kindex ptype
-Print a description of data type @var{typename}. @var{typename} may be
-the name of a type, or for C code it may have the form
-@samp{struct @var{struct-tag}}, @samp{union @var{union-tag}} or
-@samp{enum @var{enum-tag}}.@refill
+@kindex set language
+To set the language, issue the command @samp{set language @var{lang}},
+where @var{lang} is the name of a language: @code{c} or @code{modula-2}.
+For a list of the supported languages, type @samp{set language}.
+
+Setting the language manually prevents _GDBN__ from updating the working
+language automatically. This can lead to confusion if you try
+to debug a program when the working language is not the same as the
+source language, when an expression is acceptable to both
+languages---but means different things. For instance, if the current
+source file were written in C, and _GDBN__ was parsing Modula-2, a
+command such as:
-@item ptype @var{exp}
-Print a description of the type of expression @var{exp}. @code{ptype}
-differs from @code{whatis} by printing a detailed description, instead of just
-the name of the type. For example, if your program declares a variable
-as
@example
-struct complex @{double real; double imag;@} v;
+print a = b + c
@end example
+
@noindent
-compare the output of the two commands:
-@example
-(_GDBP__) whatis v
-type = struct complex
-(_GDBP__) ptype v
-type = struct complex @{
- double real;
- double imag;
-@}
-@end example
+might not have the effect you intended. In C, this means to add
+@code{b} and @code{c} and place the result in @code{a}. The result
+printed would be the value of @code{a}. In Modula-2, this means to compare
+@code{a} to the result of @code{b+c}, yielding a @code{BOOLEAN} value.
+
+If you allow _GDBN__ to set the language automatically, then
+you can count on expressions evaluating the same way in your debugging
+session and in your program.
+
+@node Automatically, , Manually, Setting
+@subsection Having _GDBN__ infer the source language
+
+To have _GDBN__ set the working language automatically, use @samp{set
+language local} or @samp{set language auto}. _GDBN__ then infers the
+language that a program was written in by looking at the name of its
+source files, and examining their extensions:
+
+@table @file
+@item *.mod
+Modula-2 source file
+
+@item *.c
+@itemx *.cc
+C or C++ source file.
+@end table
-@item info types @var{regexp}
-@itemx info types
-@kindex info types
-Print a brief description of all types whose name matches @var{regexp}
-(or all types in your program, if you supply no argument). Each
-complete typename is matched as though it were a complete line; thus,
-@samp{i type value} gives information on all types in your program whose
-name includes the string @code{value}, but @samp{i type ^value$} gives
-information only on types whose complete name is @code{value}.
+This information is recorded for each function or procedure in a source
+file. When your program stops in a frame (usually by encountering a
+breakpoint), _GDBN__ sets the working language to the language recorded
+for the function in that frame. If the language for a frame is unknown
+(that is, if the function or block corresponding to the frame was
+defined in a source file that does not have a recognized extension), the
+current working language is not changed, and _GDBN__ issues a warning.
-This command differs from @code{ptype} in two ways: first, like
-@code{whatis}, it does not print a detailed description; second, it
-lists all source files where a type is defined.
+This may not seem necessary for most programs, which are written
+entirely in one source language. However, program modules and libraries
+written in one source language can be used by a main program written in
+a different source language. Using @samp{set language auto} in this
+case frees you from having to set the working language manually.
-@item info source
+@node Show, Checks, Setting, Languages
+@section Displaying the language
+
+The following commands will help you find out which language is the
+working language, and also what language source files were written in.
+
+@kindex show language
+@kindex info frame
@kindex info source
-Show the name of the current source file---that is, the source file for
-the function containing the current point of execution.
+@table @code
+@item show language
+Display the current working language. This is the
+language you can use with commands such as @code{print} to
+build and compute expressions that may involve variables in your program.
-@item info sources
-@kindex info sources
-Print the names of all source files in the program for which there is
-debugging information, organized into two lists: those for which symbols
-have been read in, and those for which symbols will be read in on
-demand.
-@c FIXME: above passive AND awkward!
+@item info frame
+Among the other information listed here (@pxref{Frame Info,,Information
+about a Frame}) is the source language for this frame. This is the
+language that will become the working language if you ever use an
+identifier that is in this frame.
-@item info functions
-@kindex info functions
-Print the names and data types of all defined functions.
+@item info source
+Among the other information listed here (@pxref{Symbols,,Examining the
+Symbol Table}) is the source language of this source file.
-@item info functions @var{regexp}
-Print the names and data types of all defined functions
-whose names contain a match for regular expression @var{regexp}.
-Thus, @samp{info fun step} finds all functions whose names
-include @code{step}; @samp{info fun ^step} finds those whose names
-start with @code{step}.
+@end table
-@item info variables
-@kindex info variables
-Print the names and data types of all variables that are declared
-outside of functions (i.e., excluding local variables).
+@node Checks, Support, Show, Languages
+@section Type and range Checking
-@item info variables @var{regexp}
-Print the names and data types of all variables (except for local
-variables) whose names contain a match for regular expression
-@var{regexp}.
+@quotation
+@emph{Warning:} In this release, the _GDBN__ commands for type and range
+checking are included, but they do not yet have any effect. This
+section documents the intended facilities.
+@end quotation
+@c FIXME remove warning when type/range code added
+
+Some languages are designed to guard you against making seemingly common
+errors through a series of compile- and run-time checks. These include
+checking the type of arguments to functions and operators, and making
+sure mathematical overflows are caught at run time. Checks such as
+these help to ensure a program's correctness once it has been compiled
+by eliminating type mismatches, and providing active checks for range
+errors when your program is running.
+
+_GDBN__ can check for conditions like the above if you wish. Although
+_GDBN__ will not check the statements in your program, it can check
+expressions entered directly into _GDBN__ for evaluation via the
+@code{print} command, for example. As with the working language,
+_GDBN__ can also decide whether or not to check automatically based on
+your program's source language. @xref{Support,,Supported Languages},
+for the default settings of supported languages.@refill
+@menu
+* Type Checking:: An overview of type checking
+* Range Checking:: An overview of range checking
+@end menu
-@ignore
-This was never implemented.
+@cindex type checking
+@cindex checks, type
+@node Type Checking, Range Checking, Checks, Checks
+@subsection An overview of type checking
+
+Some languages, such as Modula-2, are strongly typed, meaning that the
+arguments to operators and functions have to be of the correct type,
+otherwise an error occurs. These checks prevent type mismatch
+errors from ever causing any run-time problems. For example,
+
+@example
+1 + 2 @result{} 3
+@error{} 1 + 2.3
+@end example
+
+The second example fails because the @code{CARDINAL} 1 is not
+type-compatible with the @code{REAL} 2.3.
+
+For expressions you use in _GDBN__ commands, you can tell the _GDBN__
+type checker to skip checking; to treat any mismatches as errors and
+abandon the expression; or only issue warnings when type mismatches
+occur, but evaluate the expression anyway. When you choose the last of
+these, _GDBN__ evaluates expressions like the second example above, but
+also issues a warning.
+
+Even though you may turn type checking off, other type-based reasons may
+prevent _GDBN__ from evaluating an expression. For instance, _GDBN__ does not
+know how to add an @code{int} and a @code{struct foo}. These particular
+type errors have nothing to do with the language in use, and usually
+arise from expressions, such as the one described above, which make
+little sense to evaluate anyway.
+
+Each language defines to what degree it is strict about type. For
+instance, both Modula-2 and C require the arguments to arithmetical
+operators to be numbers. In C, enumerated types and pointers can be
+represented as numbers, so that they are valid arguments to mathematical
+operators. @xref{Support,,Supported Languages}, for futher
+details on specific languages.
+
+_GDBN__ provides some additional commands for controlling the type checker:
+
+@kindex set check
+@kindex set check type
+@kindex show check type
+@table @code
+@item set check type auto
+Set type checking on or off based on the current working language.
+@xref{Support,,Supported Languages}, for the default settings for
+each language.
+
+@item set check type on
+@itemx set check type off
+Set type checking on or off, overriding the default setting for the
+current working language. Issue a warning if the setting does not
+match the language's default. If any type mismatches occur in
+evaluating an expression while typechecking is on, _GDBN__ prints a
+message and aborts evaluation of the expression.
+
+@item set check type warn
+Cause the type checker to issue warnings, but to always attempt to
+evaluate the expression. Evaluating the expression may still
+be impossible for other reasons. For example, _GDBN__ cannot add
+numbers and structures.
+
+@item show type
+Show the current setting of the type checker, and whether or not _GDBN__ is
+setting it automatically.
+@end table
+
+@cindex range checking
+@cindex checks, range
+@node Range Checking, , Type Checking, Checks
+@subsection An overview of Range Checking
+
+In some languages (such as Modula-2), it is an error to exceed the
+bounds of a type; this is enforced with run-time checks. Such range
+checking is meant to ensure program correctness by making sure
+computations do not overflow, or indices on an array element access do
+not exceed the bounds of the array.
+
+For expressions you use in _GDBN__ commands, you can tell _GDBN__ to
+ignore range errors; to always treat them as errors and abandon the
+expression; or to issue warnings when a range error occurs but evaluate
+the expression anyway.
+
+A range error can result from numerical overflow, from exceeding an
+array index bound, or when you type in a constant that is not a member
+of any type. Some languages, however, do not treat overflows as an
+error. In many implementations of C, mathematical overflow causes the
+result to ``wrap around'' to lower values---for example, if @var{m} is
+the largest integer value, and @var{s} is the smallest, then
+@example
+@var{m} + 1 @result{} @var{s}
+@end example
+
+This, too, is specific to individual languages, and in some cases
+specific to individual compilers or machines. @xref{Support,,
+Supported Languages}, for further details on specific languages.
+
+_GDBN__ provides some additional commands for controlling the range checker:
+
+@kindex set check
+@kindex set check range
+@kindex show check range
+@table @code
+@item set check range auto
+Set range checking on or off based on the current working language.
+@xref{Support,,Supported Languages}, for the default settings for
+each language.
+
+@item set check range on
+@itemx set check range off
+Set range checking on or off, overriding the default setting for the
+current working language. A warning is issued if the setting does not
+match the language's default. If a range error occurs, then a message
+is printed and evaluation of the expression is aborted.
+
+@item set check range warn
+Output messages when the _GDBN__ range checker detects a range error,
+but attempt to evaluate the expression anyway. Evaluating the
+expression may still be impossible for other reasons, such as accessing
+memory that the process does not own (a typical example from many UNIX
+systems).
+
+@item show range
+Show the current setting of the range checker, and whether or not it is
+being set automatically by _GDBN__.
+@end table
+
+@node Support, , Checks, Languages
+@section Supported Languages
+
+_GDBN__ _GDB_VN__ supports C, C++, and Modula-2. The syntax for C and C++ is
+so closely related that _GDBN__ does not distinguish the two. Some
+_GDBN__ features may be used in expressions regardless of the language
+you use: the _GDBN__ @code{@@} and @code{::} operators, and the
+@samp{@{type@}addr} construct (@pxref{Expressions}) can be used with the constructs of
+any of the supported languages.
+
+The following sections detail to what degree each of these
+source languages is supported by _GDBN__. These sections are
+not meant to be language tutorials or references, but serve only as a
+reference guide to what the _GDBN__ expression parser will accept, and
+what input and output formats should look like for different languages.
+There are many good books written on each of these languages; please
+look to these for a language reference or tutorial.
+
+@menu
+* C:: C and C++
+* Modula-2:: Modula-2
+@end menu
+
+@node C, Modula-2, Support, Support
+@subsection C and C++
+@cindex C and C++
+
+@cindex expressions in C or C++
+Since C and C++ are so closely related, _GDBN__ does not distinguish
+between them when interpreting the expressions recognized in _GDBN__
+commands.
+
+@cindex C++
+@kindex g++
+@cindex GNU C++
+The C++ debugging facilities are jointly implemented by the GNU C++
+compiler and _GDBN__. Therefore, to debug your C++ code effectively,
+you must compile your C++ programs with the GNU C++ compiler,
+@code{g++}.
+
+
+@menu
+* C Operators:: C and C++ Operators
+* C Constants:: C and C++ Constants
+* Cplusplus expressions:: C++ Expressions
+* C Defaults:: Default settings for C and C++
+* C Checks:: C and C++ Type and Range Checks
+* Debugging C:: _GDBN__ and C
+* Debugging C plus plus:: Special features for C++
+@end menu
+
+@cindex C and C++ operators
+@node C Operators, C Constants, C, C
+@subsubsection C and C++ Operators
+
+Operators must be defined on values of specific types. For instance,
+@code{+} is defined on numbers, but not on structures. Operators are
+often defined on groups of types. For the purposes of C and C++, the
+following definitions hold:
+
+@itemize @bullet
+@item
+@emph{Integral types} include @code{int} with any of its storage-class
+specifiers, @code{char}, and @code{enum}s.
+
+@item
+@emph{Floating-point types} include @code{float} and @code{double}.
+
+@item
+@emph{Pointer types} include all types defined as @code{(@var{type}
+*)}.
+
+@item
+@emph{Scalar types} include all of the above.
+
+@end itemize
+
+@noindent
+The following operators are supported. They are listed here
+in order of increasing precedence:
+
+@table @code
+_0__
+@item ,
+The comma or sequencing operator. Expressions in a comma-separated list
+are evaluated from left to right, with the result of the entire
+expression being the last expression evaluated.
+
+@item =
+Assignment. The value of an assignment expression is the value
+assigned. Defined on scalar types.
+
+@item @var{op}=
+Used in an expression of the form @var{a} @var{op}@code{=} @var{b}, and
+translated to @var{a} @code{=} @var{a op b}. @var{op}@code{=} and
+@code{=} have the same precendence. @var{op} is any one of the
+operators @code{|}, @code{^}, @code{&}, @code{<<}, @code{>>}, @code{+},
+@code{-}, @code{*}, @code{/}, @code{%}.
+
+@item ?:
+The ternary operator. @code{@var{a} ? @var{b} : @var{c}} can be thought
+of as: if @var{a} then @var{b} else @var{c}. @var{a} should be of an
+integral type.
+
+@item ||
+Logical OR. Defined on integral types.
+
+@item &&
+Logical AND. Defined on integral types.
+
+@item |
+Bitwise OR. Defined on integral types.
+
+@item ^
+Bitwise exclusive-OR. Defined on integral types.
+
+@item &
+Bitwise AND. Defined on integral types.
+
+@item ==@r{, }!=
+Equality and inequality. Defined on scalar types. The value of these
+expressions is 0 for false and non-zero for true.
+
+@item <@r{, }>@r{, }<=@r{, }>=
+Less than, greater than, less than or equal, greater than or equal.
+Defined on scalar types. The value of these expressions is 0 for false
+and non-zero for true.
+
+@item <<@r{, }>>
+left shift, and right shift. Defined on integral types.
+
+@item @@
+The _GDBN__ ``artificial array'' operator (@pxref{Expressions}).
+
+@item +@r{, }-
+Addition and subtraction. Defined on integral types, floating-point types and
+pointer types.
+
+@item *@r{, }/@r{, }%
+Multiplication, division, and modulus. Multiplication and division are
+defined on integral and floating-point types. Modulus is defined on
+integral types.
+
+@item ++@r{, }--
+Increment and decrement. When appearing before a variable, the
+operation is performed before the variable is used in an expression;
+when appearing after it, the variable's value is used before the
+operation takes place.
+
+@item *
+Pointer dereferencing. Defined on pointer types. Same precedence as
+@code{++}.
+
+@item &
+Address operator. Defined on variables. Same precedence as @code{++}.
+
+@item -
+Negative. Defined on integral and floating-point types. Same
+precedence as @code{++}.
+
+@item !
+Logical negation. Defined on integral types. Same precedence as
+@code{++}.
+
+@item ~
+Bitwise complement operator. Defined on integral types. Same precedence as
+@code{++}.
+
+@item .@r{, }->
+Structure member, and pointer-to-structure member. For convenience,
+_GDBN__ regards the two as equivalent, choosing whether to dereference a
+pointer based on the stored type information.
+Defined on @code{struct}s and @code{union}s.
+
+@item []
+Array indexing. @code{@var{a}[@var{i}]} is defined as
+@code{*(@var{a}+@var{i})}. Same precedence as @code{->}.
+
+@item ()
+Function parameter list. Same precedence as @code{->}.
+
+@item ::
+C++ scope resolution operator. Defined on
+@code{struct}, @code{union}, and @code{class} types.
+
+@item ::
+The _GDBN__ scope operator (@pxref{Expressions}). Same precedence as
+@code{::}, above. _1__
+@end table
+
+@cindex C and C++ constants
+@node C Constants, Cplusplus expressions, C Operators, C
+@subsubsection C and C++ Constants
+
+_GDBN__ allows you to express the constants of C and C++ in the
+following ways:
+
+@itemize @bullet
+
+@item
+Integer constants are a sequence of digits. Octal constants are
+specified by a leading @samp{0} (ie. zero), and hexadecimal constants by
+a leading @samp{0x} or @samp{0X}. Constants may also end with an
+@samp{l}, specifying that the constant should be treated as a
+@code{long} value.
+
+@item
+Floating point constants are a sequence of digits, followed by a decimal
+point, followed by a sequence of digits, and optionally followed by an
+exponent. An exponent is of the form:
+@samp{@w{e@r{[[}+@r{]|}-@r{]}@var{nnn}}}, where @var{nnn} is another
+sequence of digits. The @samp{+} is optional for positive exponents.
+
+@item
+Enumerated constants consist of enumerated identifiers, or their
+integral equivalents.
+
+@item
+Character constants are a single character surrounded by single quotes
+(@code{'}), or a number---the ordinal value of the corresponding character
+(usually its @sc{ASCII} value). Within quotes, the single character may
+be represented by a letter or by @dfn{escape sequences}, which are of
+the form @samp{\@var{nnn}}, where @var{nnn} is the octal representation
+of the character's ordinal value; or of the form @samp{\@var{x}}, where
+@samp{@var{x}} is a predefined special character---for example,
+@samp{\n} for newline.
+
+@item
+String constants are a sequence of character constants surrounded
+by double quotes (@code{"}).
+
+@item
+Pointer constants are an integral value.
+
+@end itemize
+
+
+@node Cplusplus expressions, C Defaults, C Constants, C
+@subsubsection C++ Expressions
+
+@cindex expressions in C++
+_GDBN__'s expression handling has the following extensions to
+interpret a significant subset of C++ expressions:
+
+@enumerate
+
+@cindex member functions
+@item
+Member function calls are allowed; you can use expressions like
+@example
+count = aml->GetOriginal(x, y)
+@end example
+
+@kindex this
+@cindex namespace in C++
+@item
+While a member function is active (in the selected stack frame), your
+expressions have the same namespace available as the member function;
+that is, _GDBN__ allows implicit references to the class instance
+pointer @code{this} following the same rules as C++.
+
+@cindex call overloaded functions
+@cindex type conversions in C++
+@item
+You can call overloaded functions; _GDBN__ will resolve the function
+call to the right definition, with one restriction---you must use
+arguments of the type required by the function that you want to call.
+_GDBN__ will not perform conversions requiring constructors or
+user-defined type operators.
+
+@cindex reference declarations
+@item
+_GDBN__ understands variables declared as C++ references; you can use them in
+expressions just as you do in C++ source---they are automatically
+dereferenced.
+
+In the parameter list shown when _GDBN__ displays a frame, the values of
+reference variables are not displayed (unlike other variables); this
+avoids clutter, since references are often used for large structures.
+The @emph{address} of a reference variable is always shown, unless
+you've specified @samp{set print address off}.
+
+
+@item
+_GDBN__ supports the C++ name resolution operator @code{::}---your
+expressions can use it just as expressions in your program do. Since
+one scope may be defined in another, you can use @code{::} repeatedly if
+necessary, for example in an expression like
+@samp{@var{scope1}::@var{scope2}::@var{name}}. _GDBN__ also allows
+resolving name scope by reference to source files, in both C and C++
+debugging; @pxref{Variables}.
+
+@end enumerate
+
+
+@node C Defaults, C Checks, Cplusplus expressions, C
+@subsubsection C and C++ Defaults
+@cindex C and C++ defaults
+
+If you allow _GDBN__ to set type and range checking automatically, they
+both default to @code{off} whenever the working language changes to
+C/C++. This happens regardless of whether you, or _GDBN__,
+selected the working language.
+
+If you allow _GDBN__ to set the language automatically, it sets the
+working language to C/C++ on entering code compiled from a source file
+whose name ends with @file{.c} or @file{.cc}.
+@xref{Automatically,,Having _GDBN__ infer the source language}, for
+further details.
+
+@node C Checks, Debugging C, C Defaults, C
+@subsubsection C and C++ Type and Range Checks
+@cindex C and C++ checks
+
+@quotation
+@emph{Warning:} in this release, _GDBN__ does not yet perform type or
+range checking.
+@end quotation
+@c FIXME remove warning when type/range checks added
+
+By default, when _GDBN__ parses C or C++ expressions, type checking
+is not used. However, if you turn type checking on, _GDBN__ will
+consider two variables type equivalent if:
+
+@itemize @bullet
+@item
+The two variables are structured and have the same structure, union, or
+enumerated tag.
+
+@item
+Two two variables have the same type name, or types that have been
+declared equivalent through @code{typedef}.
+
+@ignore
+@c leaving this out because neither J Gilmore nor R Pesch understand it.
+@c FIXME--beers?
+@item
+The two @code{struct}, @code{union}, or @code{enum} variables are
+declared in the same declaration. (Note: this may not be true for all C
+compilers.)
+@end ignore
+
+@end itemize
+
+Range checking, if turned on, is done on mathematical operations. Array
+indices are not checked, since they are often used to index a pointer
+that is not itself an array.
+
+@node Debugging C, Debugging C plus plus, C Checks, C
+@subsubsection _GDBN__ and C
+
+The @code{set print union} and @code{show print union} commands apply to
+the @code{union} type. When set to @samp{on}, any @code{union} that is
+inside a @code{struct} or @code{class} will also be printed.
+Otherwise, it will appear as @samp{@{...@}}.
+
+The @code{@@} operator aids in the debugging of dynamic arrays, formed
+with pointers and a memory allocation function. (@pxref{Expressions})
+
+@node Debugging C plus plus, , Debugging C, C
+@subsubsection _GDBN__ Commands for C++
+
+@cindex commands for C++
+Some _GDBN__ commands are particularly useful with C++, and some are
+designed specifically for use with C++. Here is a summary:
+
+@table @code
+@cindex break in overloaded functions
+@item @r{breakpoint menus}
+When you want a breakpoint in a function whose name is overloaded,
+_GDBN__'s breakpoint menus help you specify which function definition
+you want. @xref{Breakpoint Menus}.
+
+@cindex overloading in C++
+@item rbreak @var{regex}
+Setting breakpoints using regular expressions is helpful for setting
+breakpoints on overloaded functions that are not members of any special
+classes.
+@xref{Set Breaks, ,Setting Breakpoints}.
+
+@cindex C++ exception handling
+@item catch @var{exceptions}
+@itemx info catch
+Debug C++ exception handling using these commands. @xref{Exception
+Handling, ,Breakpoints and Exceptions}. @refill
+
+@cindex inheritance
+@item ptype @var{typename}
+Print inheritance relationships as well as other information for type
+@var{typename}.
+@xref{Symbols}.
+
+@cindex C++ symbol display
+@item set print demangle
+@itemx show print demangle
+@itemx set print asm-demangle
+@itemx show print asm-demangle
+Control whether C++ symbols display in their source form, both when
+displaying code as C++ source and when displaying disassemblies.
+@xref{Print Settings}.
+
+@item set print object
+@itemx show print object
+Choose whether to print derived (actual) or declared types of objects.
+@xref{Print Settings}.
+
+@item set print vtbl
+@itemx show print vtbl
+Control the format for printing virtual function tables.
+@xref{Print Settings}.
+
+@end table
+
+
+@node Modula-2, , C, Support
+@subsection Modula-2
+@cindex Modula-2
+
+The extensions made to _GDBN__ to support Modula-2 support output
+from the GNU Modula-2 compiler (which is currently being developed).
+Other Modula-2 compilers are not currently supported, and attempting to
+debug executables produced by them will most likely result in an error
+as _GDBN__ reads in the executable's symbol table.
+
+@cindex expressions in Modula-2
+@menu
+* M2 Operators:: Built-in operators
+* Built-In Func/Proc:: Built-in Functions and Procedures
+* M2 Constants:: Modula-2 Constants
+* M2 Defaults:: Default settings for Modula-2
+* Deviations:: Deviations from standard Modula-2
+* M2 Checks:: Modula-2 Type and Range Checks
+* M2 Scope:: The scope operators @code{::} and @code{.}
+* GDB/M2:: _GDBN__ and Modula-2
+@end menu
+
+@node M2 Operators, Built-In Func/Proc, Modula-2, Modula-2
+@subsubsection Operators
+@cindex Modula-2 operators
+
+Operators must be defined on values of specific types. For instance,
+@code{+} is defined on numbers, but not on structures. Operators are
+often defined on groups of types. For the purposes of Modula-2, the
+following definitions hold:
+
+@itemize @bullet
+
+@item
+@emph{Integral types} consist of @code{INTEGER}, @code{CARDINAL}, and
+their subranges.
+
+@item
+@emph{Character types} consist of @code{CHAR} and its subranges.
+
+@item
+@emph{Floating-point types} consist of @code{REAL}.
+
+@item
+@emph{Pointer types} consist of anything declared as @code{POINTER TO
+@var{type}}.
+
+@item
+@emph{Scalar types} consist of all of the above.
+
+@item
+@emph{Set types} consist of @code{SET}s and @code{BITSET}s.
+
+@item
+@emph{Boolean types} consist of @code{BOOLEAN}.
+
+@end itemize
+
+@noindent
+The following operators are supported, and appear in order of
+increasing precedence:
+
+@table @code
+_0__
+@item ,
+Function argument or array index separator.
+
+@item :=
+Assignment. The value of @var{var} @code{:=} @var{value} is
+@var{value}.
+
+@item <@r{, }>
+Less than, greater than on integral, floating-point, or enumerated
+types.
+
+@item <=@r{, }>=
+Less than, greater than, less than or equal to, greater than or equal to
+on integral, floating-point and enumerated types, or set inclusion on
+set types. Same precedence as @code{<}.
+
+@item =@r{, }<>@r{, }#
+Equality and two ways of expressing inequality, valid on scalar types.
+Same precedence as @code{<}. In _GDBN__ scripts, only @code{<>} is
+available for inequality, since @code{#} conflicts with the script
+comment character.
+
+@item IN
+Set membership. Defined on set types and the types of their members.
+Same precedence as @code{<}.
+
+@item OR
+Boolean disjunction. Defined on boolean types.
+
+@item AND@r{, }&
+Boolean conjuction. Defined on boolean types.
+
+@item @@
+The _GDBN__ ``artificial array'' operator (@pxref{Expressions}).
+
+@item +@r{, }-
+Addition and subtraction on integral and floating-point types, or union
+and difference on set types.
+
+@item *
+Multiplication on integral and floating-point types, or set intersection
+on set types.
+
+@item /
+Division on floating-point types, or symmetric set difference on set
+types. Same precedence as @code{*}.
+
+@item DIV@r{, }MOD
+Integer division and remainder. Defined on integral types. Same
+precedence as @code{*}.
+
+@item -
+Negative. Defined on @code{INTEGER}s and @code{REAL}s.
+
+@item ^
+Pointer dereferencing. Defined on pointer types.
+
+@item NOT
+Boolean negation. Defined on boolean types. Same precedence as
+@code{^}.
+
+@item .
+@code{RECORD} field selector. Defined on @code{RECORD}s. Same
+precedence as @code{^}.
+
+@item []
+Array indexing. Defined on @code{ARRAY}s. Same precedence as @code{^}.
+
+@item ()
+Procedure argument list. Defined on @code{PROCEDURE}s. Same precedence
+as @code{^}.
+
+@item ::@r{, }.
+_GDBN__ and Modula-2 scope operators.
+
+@end table
+
+@quotation
+@emph{Warning:} Sets and their operations are not yet supported, so _GDBN__
+will treat the use of the operator @code{IN}, or the use of operators
+@code{+}, @code{-}, @code{*}, @code{/}, @code{=}, , @code{<>}, @code{#},
+@code{<=}, and @code{>=} on sets as an error.
+@end quotation
+_1__
+
+@cindex Modula-2 built-ins
+@node Built-In Func/Proc, M2 Constants, M2 Operators, Modula-2
+@subsubsection Built-in Functions and Procedures
+
+Modula-2 also makes available several built-in procedures and functions.
+In describing these, the following metavariables are used:
+
+@table @var
+
+@item a
+represents an @code{ARRAY} variable.
+
+@item c
+represents a @code{CHAR} constant or variable.
+
+@item i
+represents a variable or constant of integral type.
+
+@item m
+represents an identifier that belongs to a set. Generally used in the
+same function with the metavariable @var{s}. The type of @var{s} should
+be @code{SET OF @var{mtype}} (where @var{mtype} is the type of @var{m}.
+
+@item n
+represents a variable or constant of integral or floating-point type.
+
+@item r
+represents a variable or constant of floating-point type.
+
+@item t
+represents a type.
+
+@item v
+represents a variable.
+
+@item x
+represents a variable or constant of one of many types. See the
+explanation of the function for details.
+
+@end table
+
+All Modula-2 built-in procedures also return a result, described below.
+
+@table @code
+@item ABS(@var{n})
+Returns the absolute value of @var{n}.
+
+@item CAP(@var{c})
+If @var{c} is a lower case letter, it returns its upper case
+equivalent, otherwise it returns its argument
+
+@item CHR(@var{i})
+Returns the character whose ordinal value is @var{i}.
+
+@item DEC(@var{v})
+Decrements the value in the variable @var{v}. Returns the new value.
+
+@item DEC(@var{v},@var{i})
+Decrements the value in the variable @var{v} by @var{i}. Returns the
+new value.
+
+@item EXCL(@var{m},@var{s})
+Removes the element @var{m} from the set @var{s}. Returns the new
+set.
+
+@item FLOAT(@var{i})
+Returns the floating point equivalent of the integer @var{i}.
+
+@item HIGH(@var{a})
+Returns the index of the last member of @var{a}.
+
+@item INC(@var{v})
+Increments the value in the variable @var{v}. Returns the new value.
+
+@item INC(@var{v},@var{i})
+Increments the value in the variable @var{v} by @var{i}. Returns the
+new value.
+
+@item INCL(@var{m},@var{s})
+Adds the element @var{m} to the set @var{s} if it is not already
+there. Returns the new set.
+
+@item MAX(@var{t})
+Returns the maximum value of the type @var{t}.
+
+@item MIN(@var{t})
+Returns the minimum value of the type @var{t}.
+
+@item ODD(@var{i})
+Returns boolean TRUE if @var{i} is an odd number.
+
+@item ORD(@var{x})
+Returns the ordinal value of its argument. For example, the ordinal
+value of a character is its ASCII value (on machines supporting the
+ASCII character set). @var{x} must be of an ordered type, which include
+integral, character and enumerated types.
+
+@item SIZE(@var{x})
+Returns the size of its argument. @var{x} can be a variable or a type.
+
+@item TRUNC(@var{r})
+Returns the integral part of @var{r}.
+
+@item VAL(@var{t},@var{i})
+Returns the member of the type @var{t} whose ordinal value is @var{i}.
+@end table
+
+@quotation
+@emph{Warning:} Sets and their operations are not yet supported, so
+_GDBN__ will treat the use of procedures @code{INCL} and @code{EXCL} as
+an error.
+@end quotation
+
+@cindex Modula-2 constants
+@node M2 Constants, M2 Defaults, Built-In Func/Proc, Modula-2
+@subsubsection Constants
+
+_GDBN__ allows you to express the constants of Modula-2 in the following
+ways:
+
+@itemize @bullet
+
+@item
+Integer constants are simply a sequence of digits. When used in an
+expression, a constant is interpreted to be type-compatible with the
+rest of the expression. Hexadecimal integers are specified by a
+trailing @samp{H}, and octal integers by a trailing @samp{B}.
+
+@item
+Floating point constants appear as a sequence of digits, followed by a
+decimal point and another sequence of digits. An optional exponent can
+then be specified, in the form @samp{E@r{[}+@r{|}-@r{]}@var{nnn}}, where
+@samp{@r{[}+@r{|}-@r{]}@var{nnn}} is the desired exponent. All of the
+digits of the floating point constant must be valid decimal (base 10)
+digits.
+
+@item
+Character constants consist of a single character enclosed by a pair of
+like quotes, either single (@code{'}) or double (@code{"}). They may
+also be expressed by their ordinal value (their ASCII value, usually)
+followed by a @samp{C}.
+
+@item
+String constants consist of a sequence of characters enclosed by a pair
+of like quotes, either single (@code{'}) or double (@code{"}). Escape
+sequences in the style of C are also allowed. @xref{C Constants}, for a
+brief explanation of escape sequences.
+
+@item
+Enumerated constants consist of an enumerated identifier.
+
+@item
+Boolean constants consist of the identifiers @code{TRUE} and
+@code{FALSE}.
+
+@item
+Pointer constants consist of integral values only.
+
+@item
+Set constants are not yet supported.
+
+@end itemize
+
+@node M2 Defaults, Deviations, M2 Constants, Modula-2
+@subsubsection Modula-2 Defaults
+@cindex Modula-2 defaults
+
+If type and range checking are set automatically by _GDBN__, they
+both default to @code{on} whenever the working language changes to
+Modula-2. This happens regardless of whether you, or _GDBN__,
+selected the working language.
+
+If you allow _GDBN__ to set the language automatically, then entering
+code compiled from a file whose name ends with @file{.mod} will set the
+working language to Modula-2. @xref{Automatically,,Having _GDBN__ set
+the language automatically}, for further details.
+
+@node Deviations, M2 Checks, M2 Defaults, Modula-2
+@subsubsection Deviations from Standard Modula-2
+@cindex Modula-2, deviations from
+
+A few changes have been made to make Modula-2 programs easier to debug.
+This is done primarily via loosening its type strictness:
+
+@itemize @bullet
+@item
+Unlike in standard Modula-2, pointer constants can be formed by
+integers. This allows you to modify pointer variables during
+debugging. (In standard Modula-2, the actual address contained in a
+pointer variable is hidden from you; it can only be modified
+through direct assignment to another pointer variable or expression that
+returned a pointer.)
+
+@item
+C escape sequences can be used in strings and characters to represent
+non-printable characters. _GDBN__ will print out strings with these
+escape sequences embedded. Single non-printable characters are
+printed using the @samp{CHR(@var{nnn})} format.
+
+@item
+The assignment operator (@code{:=}) returns the value of its right-hand
+argument.
+
+@item
+All built-in procedures both modify @emph{and} return their argument.
+
+@end itemize
+
+@node M2 Checks, M2 Scope, Deviations, Modula-2
+@subsubsection Modula-2 Type and Range Checks
+@cindex Modula-2 checks
+
+@quotation
+@emph{Warning:} in this release, _GDBN__ does not yet perform type or
+range checking.
+@end quotation
+@c FIXME remove warning when type/range checks added
+
+_GDBN__ considers two Modula-2 variables type equivalent if:
+
+@itemize @bullet
+@item
+They are of types that have been declared equivalent via a @code{TYPE
+@var{t1} = @var{t2}} statement
+
+@item
+They have been declared on the same line. (Note: This is true of the
+GNU Modula-2 compiler, but it may not be true of other compilers.)
+
+@end itemize
+
+As long as type checking is enabled, any attempt to combine variables
+whose types are not equivalent is an error.
+
+Range checking is done on all mathematical operations, assignment, array
+index bounds, and all built-in functions and procedures.
+
+@node M2 Scope, GDB/M2, M2 Checks, Modula-2
+@subsubsection The scope operators @code{::} and @code{.}
+@cindex scope
+@kindex .
+@kindex ::
+
+There are a few subtle differences between the Modula-2 scope operator
+(@code{.}) and the _GDBN__ scope operator (@code{::}). The two have
+similar syntax:
+
+@example
+
+@var{module} . @var{id}
+@var{scope} :: @var{id}
+
+@end example
+
+@noindent
+where @var{scope} is the name of a module or a procedure,
+@var{module} the name of a module, and @var{id} is any declared
+identifier within your program, except another module.
+
+Using the @code{::} operator makes _GDBN__ search the scope
+specified by @var{scope} for the identifier @var{id}. If it is not
+found in the specified scope, then _GDBN__ will search all scopes
+enclosing the one specified by @var{scope}.
+
+Using the @code{.} operator makes _GDBN__ search the current scope for
+the identifier specified by @var{id} that was imported from the
+definition module specified by @var{module}. With this operator, it is
+an error if the identifier @var{id} was not imported from definition
+module @var{module}, or if @var{id} is not an identifier in
+@var{module}.
+
+@node GDB/M2, , M2 Scope, Modula-2
+@subsubsection _GDBN__ and Modula-2
+
+Some _GDBN__ commands have little use when debugging Modula-2 programs.
+Five subcommands of @code{set print} and @code{show print} apply
+specifically to C and C++: @samp{vtbl}, @samp{demangle},
+@samp{asm-demangle}, @samp{object}, and @samp{union}. The first four
+apply to C++, and the last to C's @code{union} type, which has no direct
+analogue in Modula-2.
+
+The @code{@@} operator (@pxref{Expressions}), while available
+while using any language, is not useful with Modula-2. Its
+intent is to aid the debugging of @dfn{dynamic arrays}, which cannot be
+created in Modula-2 as they can in C or C++. However, because an
+address can be specified by an integral constant, the construct
+@samp{@{@var{type}@}@var{adrexp}} is still useful. (@pxref{Expressions})
+
+_0__
+@cindex @code{#} in Modula-2
+In _GDBN__ scripts, the Modula-2 inequality operator @code{#} is
+interpreted as the beginning of a comment. Use @code{<>} instead.
+_1__
+
+
+@node Symbols, Altering, Languages, Top
+@chapter Examining the Symbol Table
+
+The commands described in this section allow you to inquire about the
+symbols (names of variables, functions and types) defined in your
+program. This information is inherent in the text of your program and
+does not change as your program executes. _GDBN__ finds it in your
+program's symbol table, in the file indicated when you started _GDBN__
+(@pxref{File Options}), or by one of the file-management commands
+(@pxref{Files, ,Commands to Specify Files}).
+
+@table @code
+@item info address @var{symbol}
+@kindex info address
+Describe where the data for @var{symbol} is stored. For a register
+variable, this says which register it is kept in. For a non-register
+local variable, this prints the stack-frame offset at which the variable
+is always stored.
+
+Note the contrast with @samp{print &@var{symbol}}, which does not work
+at all for a register variables, and for a stack local variable prints
+the exact address of the current instantiation of the variable.
+
+@item whatis @var{exp}
+@kindex whatis
+Print the data type of expression @var{exp}. @var{exp} is not
+actually evaluated, and any side-effecting operations (such as
+assignments or function calls) inside it do not take place.
+@xref{Expressions}.
+
+@item whatis
+Print the data type of @code{$}, the last value in the value history.
+
+@item ptype @var{typename}
+@kindex ptype
+Print a description of data type @var{typename}. @var{typename} may be
+the name of a type, or for C code it may have the form
+@samp{struct @var{struct-tag}}, @samp{union @var{union-tag}} or
+@samp{enum @var{enum-tag}}.@refill
+
+@item ptype @var{exp}
+@itemx ptype
+Print a description of the type of expression @var{exp}. @code{ptype}
+differs from @code{whatis} by printing a detailed description, instead of just
+the name of the type. For example, if your program declares a variable
+as
+@example
+struct complex @{double real; double imag;@} v;
+@end example
+@noindent
+compare the output of the two commands:
+@example
+(_GDBP__) whatis v
+type = struct complex
+(_GDBP__) ptype v
+type = struct complex @{
+ double real;
+ double imag;
+@}
+@end example
+@noindent
+As with @code{whatis}, using @code{ptype} without an argument refers to
+the type of @code{$}, the last value in the value history.
+
+@item info types @var{regexp}
+@itemx info types
+@kindex info types
+Print a brief description of all types whose name matches @var{regexp}
+(or all types in your program, if you supply no argument). Each
+complete typename is matched as though it were a complete line; thus,
+@samp{i type value} gives information on all types in your program whose
+name includes the string @code{value}, but @samp{i type ^value$} gives
+information only on types whose complete name is @code{value}.
+
+This command differs from @code{ptype} in two ways: first, like
+@code{whatis}, it does not print a detailed description; second, it
+lists all source files where a type is defined.
+
+@item info source
+@kindex info source
+Show the name of the current source file---that is, the source file for
+the function containing the current point of execution---and the language
+it was written in.
+
+@item info sources
+@kindex info sources
+Print the names of all source files in your program for which there is
+debugging information, organized into two lists: files whose symbols
+have already been read, and files whose symbols will be read when needed.
+
+@item info functions
+@kindex info functions
+Print the names and data types of all defined functions.
+
+@item info functions @var{regexp}
+Print the names and data types of all defined functions
+whose names contain a match for regular expression @var{regexp}.
+Thus, @samp{info fun step} finds all functions whose names
+include @code{step}; @samp{info fun ^step} finds those whose names
+start with @code{step}.
+
+@item info variables
+@kindex info variables
+Print the names and data types of all variables that are declared
+outside of functions (i.e., excluding local variables).
+
+@item info variables @var{regexp}
+Print the names and data types of all variables (except for local
+variables) whose names contain a match for regular expression
+@var{regexp}.
+
+
+@ignore
+This was never implemented.
@item info methods
@itemx info methods @var{regexp}
@kindex info methods
@end ignore
@item printsyms @var{filename}
+@itemx printpsyms @var{filename}
@kindex printsyms
-Write a complete dump of the debugger's symbol data into the
-file @var{filename}.
+@cindex symbol dump
+@kindex printsyms
+@cindex partial symbol dump
+Write a dump of debugging symbol data into the file @var{filename}.
+These commands are used to debug the _GDBN__ symbol-reading code. Only
+symbols with debugging data are included. If you use @code{printsyms},
+_GDBN__ includes all the symbols for which it has already collected full
+details: that is, @var{filename} reflects symbols for only those files
+whose symbols _GDBN__ has read. You can use the command @code{info
+sources} to find out which files these are. If you use
+@code{printpsyms}, the dump also shows information about symbols that
+_GDBN__ only knows partially---that is, symbols defined in files that
+_GDBN__ has skimmed, but not yet read completely. The description of
+@code{symbol-file} describes how _GDBN__ reads symbols; both commands
+are described under @ref{Files, ,Commands to Specify Files}.
+
@end table
@node Altering, _GDBN__ Files, Symbols, Top
@chapter Altering Execution
-Once you think you have found an error in the program, you might want to
+Once you think you have found an error in your program, you might want to
find out for certain whether correcting the apparent error would lead to
correct results in the rest of the run. You can find the answer by
experiment, using the _GDBN__ features for altering execution of the
program.
For example, you can store new values into variables or memory
-locations, give the program a signal, restart it at a different address,
+locations, give your program a signal, restart it at a different address,
or even return prematurely from a function to its caller.
@menu
-* Assignment:: Assignment to Variables
-* Jumping:: Continuing at a Different Address
-* Signaling:: Giving the Program a Signal
-* Returning:: Returning from a Function
-* Calling:: Calling your Program's Functions
+* Assignment:: Assignment to Variables
+* Jumping:: Continuing at a Different Address
+* Signaling:: Giving your program a Signal
+* Returning:: Returning from a Function
+* Calling:: Calling your Program's Functions
+* Patching:: Patching your Program
@end menu
@node Assignment, Jumping, Altering, Altering
@noindent
would store the value 4 into the variable @code{x}, and then print the
-value of the assignment expression (which is 4). All the assignment
-operators of C are supported, including the increment operators
-@samp{++} and @samp{--}, and combining assignments such as @samp{+=} and
-_0__@samp{<<=}_1__.
+value of the assignment expression (which is 4). @xref{Languages}, for
+more information on operators in supported languages.
-@kindex set
@kindex set variable
@cindex variables, setting
If you are not interested in seeing the value of the assignment, use the
@end example
@noindent
The invalid expression, of course, is @samp{=47}. What we can do in
-order to actually set our program's variable @code{width} is
+order to actually set our program's variable @code{width} is
@example
(_GDBP__) set var width=47
@end example
freely store an integer value into a pointer variable or vice versa, and
any structure can be converted to any other structure that is the same
length or shorter.
-@comment FIXME: how do structs align/pad in these conversions?
+@comment FIXME: how do structs align/pad in these conversions?
To store values into arbitrary places in memory, use the @samp{@{@dots{}@}}
@node Jumping, Signaling, Assignment, Altering
@section Continuing at a Different Address
-Ordinarily, when you continue the program, you do so at the place where
+Ordinarily, when you continue your program, you do so at the place where
it stopped, with the @code{continue} command. You can instead continue at
an address of your own choosing, with the following commands:
@item jump @var{linespec}
@kindex jump
Resume execution at line @var{linespec}. Execution will stop
-immediately if there is a breakpoint there. @xref{List} for a
-description of the different forms of @var{linespec}.
+immediately if there is a breakpoint there. @xref{List, ,Printing
+Source Lines}, for a description of the different forms of
+@var{linespec}.
The @code{jump} command does not change the current stack frame, or
the stack pointer, or the contents of any memory location or any
of local variables. For this reason, the @code{jump} command requests
confirmation if the specified line is not in the function currently
executing. However, even bizarre results are predictable if you are
-well acquainted with the machine-language code of the program.
+well acquainted with the machine-language code of your program.
@item jump *@var{address}
Resume execution at the instruction at address @var{address}.
You can get much the same effect as the @code{jump} command by storing a
new value into the register @code{$pc}. The difference is that this
-does not start the program running; it only changes the address where it
+does not start your program running; it only changes the address where it
@emph{will} run when it is continued. For example,
@example
@noindent
causes the next @code{continue} command or stepping command to execute at
-address 0x485, rather than at the address where the program stopped.
+address 0x485, rather than at the address where your program stopped.
@xref{Continuing and Stepping}.
The most common occasion to use the @code{jump} command is to back up,
@node Signaling, Returning, Jumping, Altering
@c @group
-@section Giving the Program a Signal
+@section Giving your program a Signal
@table @code
@item signal @var{signalnum}
@kindex signal
-Resume execution where the program stopped, but give it immediately the
+Resume execution where your program stopped, but give it immediately the
signal number @var{signalnum}.
Alternatively, if @var{signalnum} is zero, continue execution without
-giving a signal. This is useful when the program stopped on account of
+giving a signal. This is useful when your program stopped on account of
a signal and would ordinary see the signal when resumed with the
@code{continue} command; @samp{signal 0} causes it to resume without a
signal.
You can cancel execution of a function call with the @code{return}
command. If you give an
@var{expression} argument, its value is used as the function's return
-value.
+value.
@end table
When you use @code{return}, _GDBN__ discards the selected stack frame
discarded frame return prematurely. If you wish to specify a value to
be returned, give that value as the argument to @code{return}.
-This pops the selected stack frame (@pxref{Selection}), and any other
-frames inside of it, leaving its caller as the innermost remaining
-frame. That frame becomes selected. The specified value is stored in
-the registers used for returning values of functions.
+This pops the selected stack frame (@pxref{Selection, ,Selecting a
+Frame}), and any other frames inside of it, leaving its caller as the
+innermost remaining frame. That frame becomes selected. The
+specified value is stored in the registers used for returning values
+of functions.
The @code{return} command does not resume execution; it leaves the
program stopped in the state that would exist if the function had just
-returned. In contrast, the @code{finish} command (@pxref{Continuing and
-Stepping}) resumes execution until the selected stack frame returns
-naturally.@refill
+returned. In contrast, the @code{finish} command
+(@pxref{Continuing and Stepping})
+resumes execution until the selected stack frame returns naturally.@refill
-@node Calling, , Returning, Altering
+@node Calling, Patching, Returning, Altering
@section Calling your Program's Functions
@cindex calling functions
with @code{void} returned values. The result is printed and saved in
the value history, if it is not void.
+@node Patching, , Calling, Altering
+@section Patching your Program
+@cindex patching binaries
+@cindex writing into executables
+@cindex writing into corefiles
+By default, _GDBN__ opens the file containing your program's executable
+code (or the corefile) read-only. This prevents accidental alterations
+to machine code; but it also prevents you from intentionally patching
+your program's binary.
+
+If you'd like to be able to patch the binary, you can specify that
+explicitly with the @code{set write} command. For example, you might
+want to turn on internal debugging flags, or even to make emergency
+repairs.
+
+@table @code
+@item set write on
+@itemx set write off
+@kindex set write
+If you specify @samp{set write on}, _GDBN__ will open executable and
+core files for both reading and writing; if you specify @samp{set write
+off} (the default), _GDBN__ will open them read-only.
+
+If you've already loaded a file, you must load it
+again (using the @code{exec-file} or @code{core-file} command) after
+changing @code{set write}, for your new setting to take effect.
+
+@item show write
+@kindex show write
+Display whether executable files and core files will be opened for
+writing as well as reading.
+
+@end table
+
@node _GDBN__ Files, Targets, Altering, Top
@chapter _GDBN__'s Files
@menu
-* Files:: Commands to Specify Files
-* Symbol Errors:: Errors Reading Symbol Files
+* Files:: Commands to Specify Files
+* Symbol Errors:: Errors Reading Symbol Files
@end menu
@node Files, Symbol Errors, _GDBN__ Files, _GDBN__ Files
@cindex core dump file
@cindex symbol table
_GDBN__ needs to know the file name of the program to be debugged, both in
-order to read its symbol table and in order to start the program. To
+order to read its symbol table and in order to start your program. To
debug a core dump of a previous run, _GDBN__ must be told the file name of
the core dump.
The usual way to specify the executable and core dump file names is with
the command arguments given when you start _GDBN__, as discussed in
-@pxref{Invocation}.
+@pxref{Invocation, ,Getting In and Out of _GDBN__}.
Occasionally it is necessary to change to a different file during a
_GDBN__ session. Or you may run _GDBN__ and forget to specify the files you
to run. You can change the value of this variable, for both _GDBN__ and
your program, using the @code{path} command.
+@item file
@code{file} with no argument makes _GDBN__ discard any information it
has on both executable file and the symbol table.
-@item exec-file @var{filename}
+@item exec-file @r{[} @var{filename} @r{]}
@kindex exec-file
Specify that the program to be run (but not the symbol table) is found
in @var{filename}. _GDBN__ will search the environment variable @code{PATH}
-if necessary to locate the program.
+if necessary to locate your program. Omitting @var{filename} means to
+discard information on the executable file.
-@item symbol-file @var{filename}
+@item symbol-file @r{[} @var{filename} @r{]}
@kindex symbol-file
Read symbol table information from file @var{filename}. @code{PATH} is
searched when necessary. Use the @code{file} command to get both symbol
faster. For the most part, it is invisible except for occasional pauses
while the symbol table details for a particular source file are being
read. (The @code{set verbose} command can turn these pauses into
-messages if desired. @xref{Messages/Warnings}).
+messages if desired. @xref{Messages/Warnings, ,Optional Warnings and
+Messages}.)
When the symbol table is stored in COFF format, @code{symbol-file} does
read the symbol table data in full right away. We haven't implemented
usually obtained from GNU compilers; for example, using @code{_GCC__}
you can generate debugging information for optimized code.
-@item core-file @var{filename}
-@itemx core @var{filename}
+@item core-file @r{[} @var{filename} @r{]}
@kindex core
@kindex core-file
Specify the whereabouts of a core dump file to be used as the ``contents
to be used.
Note that the core file is ignored when your program is actually running
-under _GDBN__. So, if you have been running the program and you wish to
+under _GDBN__. So, if you have been running your program and you wish to
debug a core file instead, you must kill the subprocess in which the
program is running. To do this, use the @code{kill} command
(@pxref{Kill Process}).
If @code{load} is not available on your _GDBN__, attempting to execute
it gets the error message ``@code{You can't do that when your target is
-@dots{}}''
+@dots{}}''
_fi__(_GENERIC__)
-_if__(_VXWORKS__)
+_if__(_VXWORKS__)
On VxWorks, @code{load} will dynamically link @var{filename} on the
current target system as well as adding its symbols in _GDBN__.
_fi__(_VXWORKS__)
@cindex download to Nindy-960
With the Nindy interface to an Intel 960 board, @code{load} will
download @var{filename} to the 960 as well as adding its symbols in
-_GDBN__.
+_GDBN__.
_fi__(_I960__)
@code{load} will not repeat if you press @key{RET} again after using it.
@kindex add-symbol-file
@cindex dynamic linking
The @code{add-symbol-file} command reads additional symbol table information
-from the file @var{filename}. You would use this command when that file
+from the file @var{filename}. You would use this command when @var{filename}
has been dynamically loaded (by some other means) into the program that
is running. @var{address} should be the memory address at which the
file has been loaded; _GDBN__ cannot figure this out for itself.
originally read with the @code{symbol-file} command. You can use the
@code{add-symbol-file} command any number of times; the new symbol data thus
read keeps adding to the old. To discard all old symbol data instead,
-use the @code{symbol-file} command.
+use the @code{symbol-file} command.
@code{add-symbol-file} will not repeat if you press @key{RET} after using it.
as arguments. _GDBN__ always converts the file name to an absolute path
name and remembers it that way.
-@kindex sharedlibrary
-@kindex share
@cindex shared libraries
-_GDBN__ supports the SunOS shared library format. Symbols from a shared
-library cannot be referenced before the shared library has been linked
-with the program. (That is to say, until after you type @code{run} and
-the function @code{main} has been entered; or when examining core
-files.) Once the shared library has been linked in, you can use the
-following commands:
+_GDBN__ supports the SunOS shared library format. _GDBN__ automatically
+loads symbol definitions from shared libraries when you use the
+@code{run} command, or when you examine a core file. (Before you issue
+the @code{run} command, _GDBN__ won't understand references to a
+function in a shared library, however---unless you are debugging a core
+file).
+@c FIXME: next _GDBN__ release should permit some refs to undef
+@c FIXME...symbols---eg in a break cmd---assuming they're from a shared lib
@table @code
-@item sharedlibrary @var{regex}
-@itemx share @var{regex}
-Load shared object library symbols for files matching a UNIX regular
-expression.
-
-@item share
-@itemx sharedlibrary
-Load symbols for all shared libraries.
-
@item info share
@itemx info sharedlibrary
@kindex info sharedlibrary
@kindex info share
-Print the names of the shared libraries which you have loaded with the
-@code{sharedlibrary} command.
-@end table
+Print the names of the shared libraries which are currently loaded.
-@code{sharedlibrary} does not repeat automatically when you press
-@key{RET} after using it once.
+@item sharedlibrary @var{regex}
+@itemx share @var{regex}
+@kindex sharedlibrary
+@kindex share
+This is an obsolescent command; you can use it to explicitly
+load shared object library symbols for files matching a UNIX regular
+expression, but as with files loaded automatically, it will only load
+shared libraries required by your program for a core file or after
+typing @code{run}. If @var{regex} is omitted all shared libraries
+required by your program are loaded.
+@end table
@node Symbol Errors, , Files, _GDBN__ Files
@section Errors Reading Symbol Files
-While a symbol file is being read, _GDBN__ will occasionally encounter
+While reading a symbol file, _GDBN__ will occasionally encounter
problems, such as symbol types it does not recognize, or known bugs in
-compiler output. By default, it prints one message about each such
-type of problem, no matter how many times the problem occurs. You can
-ask it to print more messages, to see how many times the problems occur,
-or can shut the messages off entirely, with the @code{set
-complaints} command (@xref{Messages/Warnings}).
+compiler output. By default, _GDBN__ does not notify you of such
+problems, since they're relatively common and primarily of interest to
+people debugging compilers. If you are interested in seeing information
+about ill-constructed symbol tables, you can either ask _GDBN__ to print
+only one message about each such type of problem, no matter how many
+times the problem occurs; or you can ask _GDBN__ to print more messages,
+to see how many times the problems occur, with the @code{set complaints}
+command (@pxref{Messages/Warnings, ,Optional Warnings and Messages}).
The messages currently printed, and their meanings, are:
The symbol information shows where symbol scopes begin and end
(such as at the start of a function or a block of statements). This
error indicates that an inner scope block is not fully contained
-in its outer scope blocks.
+in its outer scope blocks.
_GDBN__ circumvents the problem by treating the inner block as if it had
the same scope as the outer block. In the error message, @var{symbol}
@item block at @var{address} out of order
-The symbol information for symbol scope blocks should occur in
+The symbol information for symbol scope blocks should occur in
order of increasing addresses. This error indicates that it does not
-do so.
+do so.
_GDBN__ does not circumvent this problem, and will have trouble locating
symbols in the source file whose symbols being read. (You can often
determine what source file is affected by specifying @code{set verbose
-on}. @xref{Messages/Warnings}.)
+on}. @xref{Messages/Warnings, ,Optional Warnings and Messages}.)
@item bad block start address patched
The symbol information for a symbol scope block has a start address
smaller than the address of the preceding source line. This is known
-to occur in the SunOS 4.1.1 (and earlier) C compiler.
+to occur in the SunOS 4.1.1 (and earlier) C compiler.
_GDBN__ circumvents the problem by treating the symbol scope block as
starting on the previous source line.
-@c @item{encountered DBX-style class variable debugging information.
-@c You seem to have compiled your program with "g++ -g0" instead of "g++ -g".
-@c Therefore _GDBN__ will not know about your class variables}
-@c
-@c This error indicates that the symbol information produced for a C++
-@c program includes zero-size fields, which indicated static fields in
-@c a previous release of the G++ compiler. This message is probably
-@c obsolete.
-@c
@item bad string table offset in symbol @var{n}
@cindex foo
Symbol number @var{n} contains a pointer into the string table which is
-larger than the size of the string table.
+larger than the size of the string table.
_GDBN__ circumvents the problem by considering the symbol to have the
name @code{foo}, which may cause other problems if many symbols end up
The symbol information contains new data types that _GDBN__ does not yet
know how to read. @code{0x@var{nn}} is the symbol type of the misunderstood
-information, in hexadecimal.
+information, in hexadecimal.
_GDBN__ circumvents the error by ignoring this symbol information. This
-will usually allow the program to be debugged, though certain symbols
+will usually allow your program to be debugged, though certain symbols
will not be accessible. If you encounter such a problem and feel like
debugging it, you can debug @code{_GDBP__} with itself, breakpoint on
@code{complain}, then go up to the function @code{read_dbx_symtab} and
examine @code{*bufp} to see the symbol.
@item stub type has NULL name
-_GDBN__ could not find the full definition for a struct or class.
+_GDBN__ could not find the full definition for a struct or class.
-@ignore
-@c this is #if 0'd in dbxread.c as of (at least!) 17 may 1991
-@item const/volatile indicator missing, got '@var{X}'
+@item const/volatile indicator missing (ok if using g++ v1.x), got@dots{}
The symbol information for a C++ member function is missing some
-information that the compiler should have output for it.
-@end ignore
+information that recent versions of the compiler should have output
+for it.
-@item C++ type mismatch between compiler and debugger
+@item info mismatch between compiler and debugger
-_GDBN__ could not parse a type specification output by the compiler
-for some C++ object.
+_GDBN__ could not parse a type specification output by the compiler.
@end table
@node Targets, Controlling _GDBN__, _GDBN__ Files, Top
-@chapter Specifying a Debugging Target
+@chapter Specifying a Debugging Target
@cindex debugging target
@kindex target
-A @dfn{target} is an interface between the debugger and a particular
-kind of file or process.
-
-Often, you will be able to run _GDBN__ in the same host environment as the
-program you are debugging; in that case, the debugging target can just be
-specified as a side effect of the @code{file} or @code{core} commands.
-When you need more flexibility---for example, running _GDBN__ on a
-physically separate host, controlling standalone systems over a
-serial port, or realtime systems over a TCP/IP connection---you can use
-the @code{target} command.
+A @dfn{target} is the execution environment occupied by your program.
+Often, _GDBN__ runs in the same host environment as your program you are
+debugging; in that case, the debugging target is specified as a side
+effect when you use the @code{file} or @code{core} commands. When you
+need more flexibility---for example, running _GDBN__ on a physically
+separate host, or controlling a standalone system over a serial port or
+a realtime system over a TCP/IP connection---you can use the
+@code{target} command to specify one of the target types configured for
+_GDBN__ (@pxref{Target Commands}).
@menu
-* Active Targets:: Active Targets
-* Target Commands:: Commands for Managing Targets
-* Remote:: Remote Debugging
+* Active Targets:: Active Targets
+* Target Commands:: Commands for Managing Targets
+* Remote:: Remote Debugging
@end menu
@node Active Targets, Target Commands, Targets, Targets
@cindex active targets
@cindex multiple targets
-Targets are managed in three @dfn{strata} that correspond to different
-classes of target: processes, core files, and executable files. This
-allows you to (for example) start a process and inspect its activity
-without abandoning your work on a core file.
-
-More than one target can potentially respond to a request. In
-particular, when you access memory _GDBN__ will examine the three strata of
-targets until it finds a target that can handle that particular address.
-Strata are always examined in a fixed order: first a process if there is
-one, then a core file if there is one, and finally an executable file if
-there is one of those.
-
-When you specify a new target in a given stratum, it replaces any target
-previously in that stratum.
+There are three classes of targets: processes, core files, and
+executable files. _GDBN__ can work concurrently on up to three active
+targets, one in each class. This allows you to (for example) start a
+process and inspect its activity without abandoning your work on a core
+file.
-To get rid of a target without replacing it, use the @code{detach}
-command. The related command @code{attach} provides you with a way of
-choosing a particular running process as a new target. @xref{Attach}.
+If, for example, you execute @samp{gdb a.out}, then the executable file
+@code{a.out} is the only active target. If you designate a core file as
+well---presumably from a prior run that crashed and coredumped---then
+_GDBN__ has two active targets and will use them in tandem, looking
+first in the corefile target, then in the executable file, to satisfy
+requests for memory addresses. (Typically, these two classes of target
+are complementary, since core files contain only a program's
+read-write memory---variables and so on---plus machine status, while
+executable files contain only the program text and initialized data.)
+
+When you type @code{run}, your executable file becomes an active process
+target as well. When a process target is active, all _GDBN__ commands
+requesting memory addresses refer to that target; addresses in an active
+core file or executable file target are obscured while the process
+target is active.
+
+Use the @code{core-file}, and @code{exec-file} commands to select a new
+core file or executable target (@pxref{Files, ,Commands to Specify Files}). To specify as a target
+a process that's already running, use the @code{attach} command
+(@pxref{Attach, ,Debugging an Already-Running Process}.).
@node Target Commands, Remote, Active Targets, Targets
@section Commands for Managing Targets
Further @var{parameters} are interpreted by the target protocol, but
typically include things like device names or host names to connect
-with, process numbers, and baud rates.
+with, process numbers, and baud rates.
The @code{target} command will not repeat if you press @key{RET} again
after executing the command.
@kindex help target
Displays the names of all targets available. To display targets
currently selected, use either @code{info target} or @code{info files}
-(@pxref{Files}).
+(@pxref{Files, ,Commands to Specify Files}).
@item help target @var{name}
Describe a particular target, including any parameters necessary to
@end menu
_fi__(_GENERIC__)
-If you are trying to debug a program running on a machine that can't run
+If you are trying to debug a program running on a machine that cannot run
_GDBN__ in the usual way, it is often useful to use remote debugging. For
example, you might use remote debugging on an operating system kernel, or on
a small system which does not have a general purpose operating system
-powerful enough to run a full-featured debugger.
+powerful enough to run a full-featured debugger.
Some configurations of _GDBN__ have special serial or TCP/IP interfaces
to make this work with particular debugging targets. In addition,
To start remote debugging, first run _GDBN__ and specify as an executable file
the program that is running in the remote machine. This tells _GDBN__ how
-to find the program's symbols and the contents of its pure text. Then
+to find your program's symbols and the contents of its pure text. Then
establish communication using the @code{target remote} command with a device
name as an argument. For example:
command.
Other remote targets may be available in your
-configuration of _GDBN__; use @code{help targets} to list them.
+configuration of _GDBN__; use @code{help targets} to list them.
_if__(_GENERIC__)
@c Text on starting up GDB in various specific cases; it goes up front
@c in manuals configured for any of those particular situations, here
-@c otherwise.
+@c otherwise.
_include__(gdbinv-s.m4)
_fi__(_GENERIC__)
data, @pxref{Print Settings}; other settings are described here.
@menu
-* Prompt:: Prompt
-* Editing:: Command Editing
-* History:: Command History
-* Screen Size:: Screen Size
-* Numbers:: Numbers
-* Messages/Warnings:: Optional Warnings and Messages
+* Prompt:: Prompt
+* Editing:: Command Editing
+* History:: Command History
+* Screen Size:: Screen Size
+* Numbers:: Numbers
+* Messages/Warnings:: Optional Warnings and Messages
@end menu
@node Prompt, Editing, Controlling _GDBN__, Controlling _GDBN__
debugging sessions.
You may control the behavior of command line editing in _GDBN__ with the
-command @code{set}.
+command @code{set}.
@table @code
@kindex set editing
@cindex history expansion
History expansion assigns special meaning to the character @kbd{!}.
@iftex
-(@xref{Event Designators}.)
+(@pxref{Event Designators}.)
@end iftex
Since @kbd{!} is also the logical not operator in C, history expansion
is off by default. If you decide to enable history expansion with the
The readline code comes with more complete documentation of
editing and history expansion features. Users unfamiliar with @code{emacs}
-or @code{vi} may wish to read it.
+or @code{vi} may wish to read it.
@iftex
@xref{Command Line Editing}.
@end iftex
@kindex set radix
@item set radix @var{base}
Set the default base for numeric input and display. Supported choices
-for @var{base} are decimal 8, 10, 16. @var{base} must itself be
+for @var{base} are decimal 2, 8, 10, 16. @var{base} must itself be
specified either unambiguously or using the current default radix; for
example, any of
@example
+set radix 1010
set radix 012
set radix 10.
set radix 0xa
Currently, the messages controlled by @code{set verbose} are those which
announce that the symbol table for a source file is being read
-(@pxref{Files}, in the description of the command
+(@pxref{Files, ,Commands to Specify Files}, in the description of the command
@code{symbol-file}).
-@c The following is the right way to do it, but emacs 18.55 doesn't support
+@c The following is the right way to do it, but emacs 18.55 does not support
@c @ref, and neither the emacs lisp manual version of texinfmt or makeinfo
-@c is released.
+@c is released.
@ignore
-see @code{symbol-file} in @ref{Files}).
+see @code{symbol-file} in @ref{Files, ,Commands to Specify Files}).
@end ignore
@table @code
Displays whether @code{set verbose} is on or off.
@end table
-By default, if _GDBN__ encounters bugs in the symbol table of an object file,
-it prints a single message about each type of problem it finds, then
-shuts up (@pxref{Symbol Errors}). You can suppress these messages, or allow more than one such
-message to be printed if you want to see how frequent the problems are.
+By default, if _GDBN__ encounters bugs in the symbol table of an object
+file, it is silent; but if you are debugging a compiler, you may find
+this information useful (@pxref{Symbol Errors}).
@table @code
@kindex set complaints
@example
(_GDBP__) run
The program being debugged has been started already.
-Start it from the beginning? (y or n)
+Start it from the beginning? (y or n)
@end example
-If you're willing to unflinchingly face the consequences of your own
+If you are willing to unflinchingly face the consequences of your own
commands, you can disable this ``feature'':
@table @code
Displays state of confirmation requests.
@end table
+@c FIXME this does not really belong here. But where *does* it belong?
+@cindex reloading symbols
+Some systems allow individual object files that make up your program to
+be replaced without stopping and restarting your program.
+_if__(_VXWORKS__)
+For example, in VxWorks you can simply recompile a defective object file
+and keep on running.
+_fi__(_VXWORKS__)
+If you are running on one of these systems, you can allow _GDBN__ to
+reload the symbols for automatically relinked modules:@refill
+@table @code
+@kindex set symbol-reloading
+@item set symbol-reloading on
+Replace symbol definitions for the corresponding source file when an
+object file with a particular name is seen again.
+
+@item set symbol-reloading off
+Do Not replace symbol definitions when re-encountering object files of
+the same name. This is the default state; if you are not running on a
+system that permits automatically relinking modules, you should leave
+@code{symbol-reloading} off, since otherwise _GDBN__ may discard symbols
+when linking large programs, that may contain several modules (from
+different directories or libraries) with the same name.
+
+@item show symbol-reloading
+Show the current @code{on} or @code{off} setting.
+@end table
+
@node Sequences, Emacs, Controlling _GDBN__, Top
@chapter Canned Sequences of Commands
-Aside from breakpoint commands (@pxref{Break Commands}), _GDBN__ provides two
-ways to store sequences of commands for execution as a unit:
-user-defined commands and command files.
+Aside from breakpoint commands (@pxref{Break Commands, ,Breakpoint
+Command Lists}), _GDBN__ provides two ways to store sequences of
+commands for execution as a unit: user-defined commands and command
+files.@refill
@menu
-* Define:: User-Defined Commands
-* Command Files:: Command Files
-* Output:: Commands for Controlled Output
+* Define:: User-Defined Commands
+* Command Files:: Command Files
+* Output:: Commands for Controlled Output
@end menu
@node Define, Command Files, Sequences, Sequences
@table @code
@item echo @var{text}
@kindex echo
-@c I don't consider backslash-space a standard C escape sequence
-@c because it's not in ANSI.
+@c I do not consider backslash-space a standard C escape sequence
+@c because it is not in ANSI.
Print @var{text}. Nonprinting characters can be included in @var{text}
using C escape sequences, such as @samp{\n} to print a newline. @b{No
newline will be printed unless you specify one.} In addition to the
beginning or the end, since leading and trailing spaces are otherwise
trimmed from all arguments. Thus, to print @samp{@ and foo =@ }, use the
command @samp{echo \@ and foo = \@ }.
-@c FIXME: verify hard copy actually issues enspaces for '@ '! Will this
-@c confuse texinfo?
+@c FIXME? '@ ' works in tex and info, but confuses texi2roff[-2].
A backslash at the end of @var{text} can be used, as in C, to continue
the command onto subsequent lines. For example,
Print the value of @var{expression} and nothing but that value: no
newlines, no @samp{$@var{nn} = }. The value is not entered in the
value history either. @xref{Expressions} for more information on
-expressions.
+expressions.
@item output/@var{fmt} @var{expression}
Print the value of @var{expression} in format @var{fmt}. You can use
Print the values of the @var{expressions} under the control of
@var{string}. The @var{expressions} are separated by commas and may
be either numbers or pointers. Their values are printed as specified
-by @var{string}, exactly as if the program were to execute
+by @var{string}, exactly as if your program were to execute
@example
printf (@var{string}, @var{expressions}@dots{});
@itemize @bullet
@item
-All ``terminal'' input and output goes through the Emacs buffer.
+All ``terminal'' input and output goes through the Emacs buffer.
@end itemize
This applies both to _GDBN__ commands and their output, and to the input
@itemize @bullet
@item
-_GDBN__ displays source code through Emacs.
+_GDBN__ displays source code through Emacs.
@end itemize
Each time _GDBN__ displays a stack frame, Emacs automatically finds the
the source files, in which case the auxiliary display buffer will not
appear to show your source. _GDBN__ can find programs by searching your
environment's @code{PATH} variable, so the _GDBN__ input and output
-session will proceed normally; but Emacs doesn't get enough information
+session will proceed normally; but Emacs does not get enough information
back from _GDBN__ to locate the source files in this situation. To
avoid this problem, either start _GDBN__ mode from the directory where
your program resides, or specify a full path name when prompted for the
@code{finish} command.
@item M-c
-Continue execution of the program, like the _GDBN__ @code{continue}
-command. @emph{Warning:} In Emacs v19, this command is @kbd{C-c C-p}.
+Continue execution of your program, like the _GDBN__ @code{continue}
+command.
+
+@emph{Warning:} In Emacs v19, this command is @kbd{C-c C-p}.
@item M-u
Go up the number of frames indicated by the numeric argument
(@pxref{Arguments, , Numeric Arguments, emacs, The GNU Emacs Manual}),
-like the _GDBN__ @code{up} command. @emph{Warning:} In Emacs v19, this
-command is @kbd{C-c C-u}.@refill
+like the _GDBN__ @code{up} command.
+
+@emph{Warning:} In Emacs v19, this command is @kbd{C-c C-u}.@refill
@item M-d
Go down the number of frames indicated by the numeric argument, like the
-_GDBN__ @code{down} command. @emph{Warning:} In Emacs v19, this command
-is @kbd{C-c C-d}.
+_GDBN__ @code{down} command.
+
+@emph{Warning:} In Emacs v19, this command is @kbd{C-c C-d}.
@item C-x &
Read the number where the cursor is positioned, and insert it at the end
of the _GDBN__ I/O buffer. For example, if you wish to disassemble code
around an address that was displayed earlier, type @kbd{disassemble};
then move the cursor to the address display, and pick up the
-argument for @code{disassemble} by typing @kbd{C-x &}.
+argument for @code{disassemble} by typing @kbd{C-x &}.
You can customize this further on the fly by defining elements of the list
@code{gdb-print-command}; once it is defined, you can format or
otherwise process numbers picked up by @kbd{C-x &} before they are
-inserted. A numeric argument to @kbd{C-x &} will both flag that you
+inserted. A numeric argument to @kbd{C-x &} will both indicate that you
wish special formatting, and act as an index to pick an element of the
list. If the list element is a string, the number to be inserted is
formatted using the Emacs function @code{format}; otherwise the number
@c The following dropped because Epoch is nonstandard. Reactivate
@ignore
-@kindex emacs epoch environment
+@kindex emacs epoch environment
@kindex epoch
@kindex inspect
information that enables us to fix the bug.
@menu
-* Bug Criteria:: Have You Found a Bug?
-* Bug Reporting:: How to Report Bugs
+* Bug Criteria:: Have You Found a Bug?
+* Bug Reporting:: How to Report Bugs
@end menu
@node Bug Criteria, Bug Reporting, _GDBN__ Bugs, _GDBN__ Bugs
A number of companies and individuals offer support for GNU products.
If you obtained _GDBN__ from a support organization, we recommend you
-contact that organization first.
+contact that organization first.
Contact information for many support companies and individuals is
available in the file @file{etc/SERVICE} in the GNU Emacs distribution.
fact or leave it out, state it!
Often people omit facts because they think they know what causes the
-problem and assume that some details don't matter. Thus, you might
+problem and assume that some details do not matter. Thus, you might
assume that the name of the variable you use in an example does not matter.
-Well, probably it doesn't, but one cannot be sure. Perhaps the bug is a
+Well, probably it does not, but one cannot be sure. Perhaps the bug is a
stray memory reference which happens to fetch from the location where that
name is stored in memory; perhaps, if the name were different, the contents
of that location would fool the debugger into doing the right thing despite
@item
A complete input script, and all necessary source files, that will
-reproduce the bug.
+reproduce the bug.
@item
What compiler (and its version) was used to compile _GDBN__---e.g.
Of course, if you can find a simpler example to report @emph{instead}
of the original one, that is a convenience for us. Errors in the
output will be easier to spot, running under the debugger will take
-less time, etc.
+less time, etc.
-However, simplification is not vital; if you don't want to do this,
+However, simplification is not vital; if you do not want to do this,
report the bug anyway and send us the entire test case you used.
@item
A patch for the bug.
-A patch for the bug does help us if it is a good one. But don't omit
+A patch for the bug does help us if it is a good one. But do not omit
the necessary information, such as the test case, on the assumption that
a patch is all we need. We might see problems with your patch and decide
to fix the problem another way, or we might not understand it at all.
Sometimes with a program as complicated as _GDBN__ it is very hard to
construct an example that will make the program follow a certain path
-through the code. If you don't send us the example, we won't be able
+through the code. If you do not send us the example, we won't be able
to construct one, so we won't be able to verify that the bug is fixed.
-And if we can't understand what bug you are trying to fix, or why your
+And if we cannot understand what bug you are trying to fix, or why your
patch should be an improvement, we won't install it. A test case will
help us to understand.
@item
A guess about what the bug is or what it depends on.
-Such guesses are usually wrong. Even we can't guess right about such
+Such guesses are usually wrong. Even we cannot guess right about such
things without first using the debugger to find the facts.
@end itemize
@iftex
-@include rdl-apps.texinfo
+@c appendices describing GNU readline. Distributed with readline code.
+@include rluser.texinfo
+@include inc-hist.texi
@end iftex
@node Renamed Commands, Installing _GDBN__, _GDBN__ Bugs, Top
The following commands were renamed in _GDBN__ 4.0, in order to make the
command set as a whole more consistent and easier to use and remember:
-@kindex add-syms
-@kindex delete environment
-@kindex info copying
-@kindex info convenience
-@kindex info directories
-@kindex info editing
-@kindex info history
-@kindex info targets
-@kindex info values
-@kindex info version
-@kindex info warranty
-@kindex set addressprint
-@kindex set arrayprint
-@kindex set prettyprint
-@kindex set screen-height
-@kindex set screen-width
-@kindex set unionprint
-@kindex set vtblprint
-@kindex set demangle
-@kindex set asm-demangle
-@kindex set sevenbit-strings
-@kindex set array-max
-@kindex set caution
-@kindex set history write
-@kindex show addressprint
-@kindex show arrayprint
-@kindex show prettyprint
-@kindex show screen-height
-@kindex show screen-width
-@kindex show unionprint
-@kindex show vtblprint
-@kindex show demangle
-@kindex show asm-demangle
-@kindex show sevenbit-strings
-@kindex show array-max
-@kindex show caution
-@kindex show history write
-@kindex unset
-
+@kindex add-syms
+@kindex delete environment
+@kindex info copying
+@kindex info convenience
+@kindex info directories
+@kindex info editing
+@kindex info history
+@kindex info targets
+@kindex info values
+@kindex info version
+@kindex info warranty
+@kindex set addressprint
+@kindex set arrayprint
+@kindex set prettyprint
+@kindex set screen-height
+@kindex set screen-width
+@kindex set unionprint
+@kindex set vtblprint
+@kindex set demangle
+@kindex set asm-demangle
+@kindex set sevenbit-strings
+@kindex set array-max
+@kindex set caution
+@kindex set history write
+@kindex show addressprint
+@kindex show arrayprint
+@kindex show prettyprint
+@kindex show screen-height
+@kindex show screen-width
+@kindex show unionprint
+@kindex show vtblprint
+@kindex show demangle
+@kindex show asm-demangle
+@kindex show sevenbit-strings
+@kindex show array-max
+@kindex show caution
+@kindex show history write
+@kindex unset
+
+@c TEXI2ROFF-KILL
@ifinfo
-OLD COMMAND NEW COMMAND
---------------- ----------------------------------
-add-syms add-symbol-file
-delete environment unset environment
-info convenience show convenience
-info copying show copying
-info directories show directories
-info editing show commands
-info history show values
-info targets help target
-info values show values
-info version show version
-info warranty show warranty
-set/show addressprint set/show print address
-set/show array-max set/show print elements
-set/show arrayprint set/show print array
-set/show asm-demangle set/show print asm-demangle
-set/show caution set/show confirm
-set/show demangle set/show print demangle
-set/show history write set/show history save
-set/show prettyprint set/show print pretty
-set/show screen-height set/show height
-set/show screen-width set/show width
-set/show sevenbit-strings set/show print sevenbit-strings
-set/show unionprint set/show print union
-set/show vtblprint set/show print vtbl
-
-unset [ No longer an alias for delete ]
+@c END TEXI2ROFF-KILL
+@example
+OLD COMMAND NEW COMMAND
+@c TEXI2ROFF-KILL
+--------------- -------------------------------
+@c END TEXI2ROFF-KILL
+add-syms add-symbol-file
+delete environment unset environment
+info convenience show convenience
+info copying show copying
+info directories show directories
+info editing show commands
+info history show values
+info targets help target
+info values show values
+info version show version
+info warranty show warranty
+set/show addressprint set/show print address
+set/show array-max set/show print elements
+set/show arrayprint set/show print array
+set/show asm-demangle set/show print asm-demangle
+set/show caution set/show confirm
+set/show demangle set/show print demangle
+set/show history write set/show history save
+set/show prettyprint set/show print pretty
+set/show screen-height set/show height
+set/show screen-width set/show width
+set/show sevenbit-strings set/show print sevenbit-strings
+set/show unionprint set/show print union
+set/show vtblprint set/show print vtbl
+
+unset [No longer an alias for delete]
+@end example
+@c TEXI2ROFF-KILL
@end ifinfo
@tex
unset &&\rm(No longer an alias for delete)\cr
}
@end tex
+@c END TEXI2ROFF-KILL
@node Installing _GDBN__, Copying, Renamed Commands, Top
@appendix Installing _GDBN__
@cindex configuring _GDBN__
@cindex installation
-_GDBN__ is distributed with a @code{configure} script that automates the
-process of preparing _GDBN__ for installation; you can then use
-@code{make} to build the @code{_GDBP__} program.
-
-The @code{configure} script that's specific to _GDBN__ is distributed in
-the main _GDBN__ source directory. However, building _GDBN__ also
-requires several other directories of source common to multiple @sc{gnu}
-programs. These directories (@sc{gnu} libraries and includes) are
-distributed separately, but their @code{configure} scripts and
-@code{Makefile}s are designed to work together. To ensure that
-_GDBN__'s @code{Makefile} can find all the pieces, you should make a
-single overall directory to hold the directories of source for @sc{gnu}
-libraries and includes, and you should install the _GDBN__ source
-directory there too. In this Appendix, we refer to the directory of
-@sc{gnu} source directories as @var{gnusrc}.
-
-At a minimum, to build _GDBN__ you need the directories
+_GDBN__ comes with a @code{configure} script that automates the process
+of preparing _GDBN__ for installation; you can then use @code{make} to
+build the @code{_GDBP__} program.
+
+The _GDBP__ distribution includes all the source code you need for
+_GDBP__ in a single directory @file{gdb-_GDB_VN__}. That directory in turn
+contains:
+
@table @code
-@item @var{gnusrc}/gdb
+@item gdb-_GDB_VN__/configure @r{(and supporting files)}
+script for configuring _GDBN__ and all its supporting libraries.
+
+@item gdb-_GDB_VN__/gdb
the source specific to _GDBN__ itself
-@item @var{gnusrc}/bfd
+@item gdb-_GDB_VN__/bfd
source for the Binary File Descriptor Library
-@item @var{gnusrc}/include
-@sc{gnu} include files
+@item gdb-_GDB_VN__/include
+GNU include files
-@item @var{gnusrc}/libiberty
+@item gdb-_GDB_VN__/libiberty
source for the @samp{-liberty} free software library
-@item @var{gnusrc}/readline
-source for the @sc{gnu} command-line interface
+@item gdb-_GDB_VN__/readline
+source for the GNU command-line interface
@end table
@noindent
-Each of these directories has its own @code{configure} script.
-@var{gnusrc} has an overall @code{configure} script, which is
-distributed with the @sc{gnu} libraries and includes.
-
-@code{configure} is designed to be called recursively, so it is most
-convenient to run @code{configure} from the @var{gnusrc} directory.
-The simplest way to configure and build _GDBN__ is the following:
+It is most convenient to run @code{configure} from the @file{gdb-_GDB_VN__}
+directory. The simplest way to configure and build _GDBN__ is the
+following:
@example
-cd @var{gnusrc}
+cd gdb-_GDB_VN__
./configure @var{host}
make
@end example
@noindent
-where @var{host} is something like @samp{sun4} or @samp{vax}, that
+where @var{host} is something like @samp{sun4} or @samp{decstation}, that
identifies the platform where _GDBN__ will run. This builds the three
libraries @file{bfd}, @file{readline}, and @file{libiberty}, then
@code{gdb} itself. The configured source files, and the binaries, are
left in the corresponding source directories.
-You can install @code{_GDBP__} anywhere; it has no hardwired paths. However,
-you should make sure that the shell on your path (named by the
+@code{configure} is a Bourne-shell (@code{/bin/sh}) script; if your
+system does not recognize this automatically when you run a different
+shell, you may need to run @code{sh} on it explicitly:
+@samp{sh configure @var{host}}.
+
+You can @emph{run} the @code{configure} script from any of the
+subordinate directories in the _GDBN__ distribution (if you only want to
+configure that subdirectory); but be sure to specify a path to it. For
+example, to configure only the @code{bfd} subdirectory,
+@example
+@group
+cd gdb-_GDB_VN__/bfd
+../configure @var{host}
+@end group
+@end example
+
+You can install @code{_GDBP__} anywhere; it has no hardwired paths.
+Simply copy @code{gdb/gdb} to the desired directory.
+@comment What about installing the man pages, info files, etc?
+
+However, you should make sure that the shell on your path (named by the
@samp{SHELL} environment variable) is publicly readable; some systems
refuse to let _GDBN__ debug child processes whose programs are not
readable, and _GDBN__ uses the shell to start your program.
@menu
-* Subdirectories:: Configuration subdirectories
-* configure Options:: Summary of options for configure
-* Formatting Manual:: How to format and print this manual
+* Subdirectories:: Configuration subdirectories
+* Config Names:: Specifying names for hosts and targets
+* configure Options:: Summary of options for configure
+* Formatting Documentation:: How to format and print _GDBN__ documentation
@end menu
-@node Subdirectories, configure Options, Installing _GDBN__, Installing _GDBN__
+@node Subdirectories, Config Names, Installing _GDBN__, Installing _GDBN__
@section Configuration Subdirectories
-If you build _GDBN__ for several host or target machines, and if
-your @code{make} program handles the @samp{VPATH} feature
-(@sc{gnu} @code{make} does), it is most convenient instead to build
-the different _GDBN__ configurations in subdirectories (separate from
-the source). @code{configure} does this for you when you simultaneously
-specify several configurations; but it's a good habit even for a single
-configuration. You can specify the use of subdirectories using the
-@samp{+forcesubdirs} option (abbreviated @samp{+f}). For example, you
-can build _GDBN__ on a Sun 4 as follows:
+If you want to run _GDBN__ versions for several host or target machines,
+you'll need a different _GDBP__ compiled for each combination of host
+and target. @code{configure} is designed to make this easy by allowing
+you to generate each configuration in a separate subdirectory. If your
+@code{make} program handles the @samp{VPATH} feature (GNU @code{make}
+does), running @code{make} in each of these directories then builds the
+_GDBP__ program specified there.
+
+@code{configure} creates these subdirectories for you when you
+simultaneously specify several configurations; but it is a good habit
+even for a single configuration. You can specify the use of
+subdirectories using the @samp{+subdirs} option (abbreviated
+@samp{+sub}). For example, you can build _GDBN__ this way on a Sun 4 as
+follows:
@example
@group
-cd @var{gnusrc}
-./configure +f sun4
-cd Host-sun4/Target-sun4
+cd gdb-_GDB_VN__
+./configure +sub sun4
+cd H-sun4/T-sun4
make
@end group
@end example
When @code{configure} uses subdirectories to build programs or
libraries, it creates nested directories
-@file{Host-@var{host}/Target-@var{machine}}. This is because _GDBN__
-can be configured for cross-compiling: _GDBN__ can run on one machine
-(the host) while debugging programs that run on another machine (the
-target). You specify cross-debugging targets by giving the
-@samp{+target=@var{machine}} option to @code{configure}. Specifying
-only hosts still gives you two levels of subdirectory for each host,
-with the same machine-name suffix on both. On the other hand, whenever
-you specify both hosts and targets on the same command line,
+@file{H-@var{host}/T-@var{target}}. @code{configure} uses these two
+directory levels because _GDBN__ can be configured for cross-compiling:
+_GDBN__ can run on one machine (the host) while debugging programs that
+run on another machine (the target). You specify cross-debugging
+targets by giving the @samp{+target=@var{target}} option to
+@code{configure}. Specifying only hosts still gives you two levels of
+subdirectory for each host, with the same configuration suffix on both;
+that is, if you give any number of hosts but no targets, _GDBN__ will be
+configured for native debugging on each host. On the other hand,
+whenever you specify both hosts and targets on the same command line,
@code{configure} creates all combinations of the hosts and targets you
list.@refill
-When you run @code{make} to build a program or library, you must run it
-in a configured directory. If you made a single configuration,
-without subdirectories, run @code{make} in the source directory.
-If you have @file{Host-@var{host}/Target-@var{machine}} subdirectories,
-run @code{make} in those subdirectories.
-
-Each @code{configure} and @code{Makefile} under each source directory
-runs recursively, so that typing @code{make} in @var{gnusrc} (or in a
-@file{@var{gnusrc}/Host-@var{host}/Target-@var{machine}} subdirectory)
-builds all the required libraries, then _GDBN__.@refill
-
-If you run @code{configure} from a directory (such as @var{gnusrc}) that
-contains source directories for multiple libraries or programs,
-@code{configure} creates the @file{Host-@var{host}/Target-@var{machine}}
-subdirectories in each library or program's source directory. For
-example, typing:
+If you run @code{configure} from a directory (notably,
+@file{gdb-_GDB_VN__}) that contains source directories for multiple
+libraries or programs, @code{configure} creates the
+@file{H-@var{host}/T-@var{target}} subdirectories in each library or
+program's source directory. For example, typing:
@example
-cd @var{gnusrc}
-configure sun4 +target=vx960
+cd gdb-_GDB_VN__
+configure sun4 +target=vxworks960
@end example
@noindent
creates the following directories:
@example
-@var{gnusrc}/Host-sun4/Target-vx960
-@var{gnusrc}/bfd/Host-sun4/Target-vx960
-@var{gnusrc}/gdb/Host-sun4/Target-vx960
-@var{gnusrc}/gdb/libiberty/Host-sun4/Target-vx960
-@var{gnusrc}/readline/Host-sun4/Target-vx960
+gdb-_GDB_VN__/H-sun4/T-vxworks960
+gdb-_GDB_VN__/bfd/H-sun4/T-vxworks960
+gdb-_GDB_VN__/gdb/H-sun4/T-vxworks960
+gdb-_GDB_VN__/libiberty/H-sun4/T-vxworks960
+gdb-_GDB_VN__/readline/H-sun4/T-vxworks960
@end example
-@noindent
-The @code{Makefile} in @file{@var{gnusrc}/Host-sun4/Target-vx960}
-will @code{cd} to the appropriate lower-level directories
-(such as @file{@var{gnusrc}/bfd/Host-sun4/Target-vx960}), building each
-in turn.
+
+When you run @code{make} to build a program or library, you must run it
+in a configured directory. If you made a single configuration,
+without subdirectories, run @code{make} in the source directory.
+If you have @file{H-@var{host}/T-@var{target}} subdirectories,
+run @code{make} in those subdirectories.
+
+The @code{Makefile} generated by @code{configure} for each source
+directory runs recursively, so that typing @code{make} in
+@file{gdb-_GDB_VN__} (or in a
+@file{gdb-_GDB_VN__/H-@var{host}/T-@var{target}} subdirectory) builds
+all the required libraries, then _GDBN__.@refill
When you have multiple hosts or targets configured, you can run
@code{make} on them in parallel (for example, if they are NFS-mounted on
each of the hosts); they will not interfere with each other.
-@node configure Options, Formatting Manual, Subdirectories, Installing _GDBN__
+You can also use the @samp{+objdir=@var{altroot}} option to have the
+configured files placed in a parallel directory structure rather than
+alongside the source files; @pxref{configure Options}.
+
+@node Config Names, configure Options, Subdirectories, Installing _GDBN__
+@section Specifying Names for Hosts and Targets
+
+The specifications used for hosts and targets in the @code{configure}
+script are based on a three-part naming scheme, but some short predefined
+aliases are also supported. The full naming scheme encodes three pieces
+of information in the following pattern:
+@example
+@var{architecture}-@var{vendor}-@var{os}
+@end example
+
+For example, you can use the alias @code{sun4} as a @var{host} argument
+or in a @code{+target=@var{target}} option, but the equivalent full name
+is @samp{sparc-sun-sunos4}.
+
+The following table shows all the architectures, hosts, and OS prefixes
+that @code{configure} recognizes in _GDBN__ _GDB_VN__. Entries in the ``OS
+prefix'' column ending in a @samp{*} may be followed by a release number.
+
+@c TEXI2ROFF-KILL
+@ifinfo
+@c END TEXI2ROFF-KILL
+@example
+
+ARCHITECTURE VENDOR OS prefix
+@c TEXI2ROFF-KILL
+------------+--------------------------+---------------------------
+@c END TEXI2ROFF-KILL
+ | |
+ 580 | altos hp | aix* msdos*
+ a29k | amd ibm | amigados newsos*
+ alliant | amdahl intel | aout nindy*
+ arm | aout isi | bout osf*
+ c1 | apollo little | bsd* sco*
+ c2 | att mips | coff sunos*
+ cray2 | bcs motorola | ctix* svr4
+ h8300 | bout ncr | dgux* sym*
+ i386 | bull next | dynix* sysv*
+ i860 | cbm nyu | ebmon ultrix*
+ i960 | coff sco | esix* unicos*
+ m68000 | convergent sequent | hds unos*
+ m68k | convex sgi | hpux* uts
+ m88k | cray sony | irix* v88r*
+ mips | dec sun | isc* vms*
+ ns32k | encore unicom | kern vxworks*
+ pyramid | gould utek | mach*
+ romp | hitachi wrs |
+ rs6000 | |
+ sparc | |
+ tahoe | |
+ tron | |
+ vax | |
+ xmp | |
+ ymp | |
+@end example
+@c TEXI2ROFF-KILL
+@end ifinfo
+@tex
+%\vskip\parskip
+\vskip \baselineskip
+\hfil\vbox{\offinterlineskip
+\halign{\strut\tt #\hfil\ &\vrule#&\strut\ \tt #\hfil\ &\strut\ \tt #\hfil
+\ &\vrule#&\strut\ \tt #\hfil\ &\strut\ \tt #\hfil \cr
+{\bf Architecture} &&{\bf Vendor} &&&{\bf OS prefix}\cr
+\multispan7\hrulefill\cr
+ 580 && altos & hp && aix* & msdos* \cr
+ a29k && amd & ibm && amigados & newsos* \cr
+ alliant && amdahl & intel && aout & nindy* \cr
+ arm && aout & isi && bout & osf* \cr
+ c1 && apollo & little && bsd* & sco* \cr
+ c2 && att & mips && coff & sunos* \cr
+ cray2 && bcs & motorola && ctix* & svr4 \cr
+ h8300 && bout & ncr && dgux* & sym* \cr
+ i386 && bull & next && dynix* & sysv* \cr
+ i860 && cbm & nyu && ebmon & ultrix* \cr
+ i960 && coff & sco && esix* & unicos* \cr
+ m68000 && convergent& sequent && hds & unos* \cr
+ m68k && convex & sgi && hpux* & uts \cr
+ m88k && cray & sony && irix* & v88r* \cr
+ mips && dec & sun && isc* & vms* \cr
+ ns32k && encore & unicom && kern & vxworks* \cr
+ pyramid && gould & utek && mach* & \cr
+ romp && hitachi & wrs && & \cr
+ rs6000 && & && & \cr
+ sparc && & && & \cr
+ tahoe && & && & \cr
+ tron && & && & \cr
+ vax && & && & \cr
+ xmp && & && & \cr
+ ymp && & && & \cr
+}\hfil}
+@end tex
+@c END TEXI2ROFF-KILL
+@quotation
+@emph{Warning:} @code{configure} can represent a very large number of
+combinations of architecture, vendor, and OS. There is by no means
+support available for all possible combinations!
+@end quotation
+
+The @code{configure} script accompanying _GDBN__ _GDB_VN__ does not provide
+any query facility to list all supported host and target names or
+aliases. @code{configure} calls the Bourne shell script
+@code{config.sub} to map abbreviations to full names; you can read the
+script, if you wish, or you can use it to test your guesses on
+abbreviations---for example:
+@example
+% sh config.sub sun4
+sparc-sun-sunos4
+% sh config.sub sun3
+m68k-sun-sunos4
+% sh config.sub decstation
+mips-dec-ultrix
+% sh config.sub hp300bsd
+m68k-hp-bsd
+% sh config.sub i386v
+i386-none-sysv
+% sh config.sub i486v
+*** Configuration "i486v" not recognized
+@end example
+@noindent
+@code{config.sub} is also distributed in the directory @file{gdb-_GDB_VN__}.
+
+@node configure Options, Formatting Documentation, Config Names, Installing _GDBN__
@section @code{configure} Options
Here is a summary of all the @code{configure} options and arguments that
you might use for building _GDBN__:
@example
-configure @r{[}+destdir=@var{dir}@r{]} @r{[}+forcesubdirs@r{]} @r{[}+norecur@r{]} @r{[}+rm@r{]}
- @r{[}+target=@var{machine}@dots{}@r{]} @var{host}@dots{}
+configure @r{[}+destdir=@var{dir}@r{]} @r{[}+subdirs@r{]}
+ @r{[}+objdir=@var{altroot}@r{]} @r{[}+norecursion@r{]} @r{[}+rm@r{]}
+ @r{[}+target=@var{target}@dots{}@r{]} @var{host}@dots{}
@end example
@noindent
You may introduce options with the character @samp{-} rather than
-@samp{+} if you prefer; but options introduced with @samp{+} may be truncated.
+@samp{+} if you prefer; but you may abbreviate option names if you use
+@samp{+}.
@table @code
@item +destdir=@var{dir}
If you specify @samp{+destdir=/usr/local}, for example, @code{make
install} creates @file{/usr/local/bin/gdb}.@refill
-@item +forcesubdirs
+@item +subdirs
Write configuration specific files in subdirectories of the form
@example
-Host-@var{machine}/Target-@var{machine}
+H-@var{host}/T-@var{target}
@end example
@noindent
-(and configure the @code{Makefile} to write binaries there too).
-Without this option, if you specify only one configuration for _GDBN__,
-@code{configure} will use the same directory for source, configured
-files, and binaries. This option is used automatically if you specify
-more than one @var{host} or more than one @samp{+target=@var{machine}}
-option on the @code{configure} command line.
-
-@item +norecur
+(and configure the @code{Makefile} to generate object code in
+subdirectories of this form as well). Without this option, if you
+specify only one configuration for _GDBN__, @code{configure} will use
+the same directory for source, configured files, and binaries. This
+option is used automatically if you specify more than one @var{host} or
+more than one @samp{+target=@var{target}} option on the @code{configure}
+command line.
+
+@item +norecursion
Configure only the directory where @code{configure} is executed; do not
propagate configuration to subdirectories.
+@item +objdir=@var{altroot}
+@var{altroot} is an alternative directory used as the root for
+configured files. @code{configure} will create directories under
+@var{altroot} in parallel to the source directories. If you use
+@samp{+objdir=@var{altroot}} with @samp{+subdirs}, @code{configure} also
+builds the @samp{H-@var{host}/T-@var{target}} subdirectories in the
+directory tree rooted in @var{altroot}.
+
+
@item +rm
-Remove the configuration specified by other arguments.
+Remove the configuration that the other arguments specify.
+
+@c This does not work (yet if ever). FIXME.
+@c @item +parse=@var{lang} @dots{}
+@c Configure the _GDBN__ expression parser to parse the listed languages.
+@c @samp{all} configures _GDBN__ for all supported languages. To get a
+@c list of all supported languages, omit the argument. Without this
+@c option, _GDBN__ is configured to parse all supported languages.
-@item +target=@var{machine} @dots{}
+@item +target=@var{target} @dots{}
Configure _GDBN__ for cross-debugging programs running on each specified
-@var{machine}. You may specify as many @samp{+target} options as you
-wish. To see a list of available targets, execute @samp{ls tconfig} in
-the _GDBN__ source directory. Without this option, _GDBN__ is
-configured to debug programs that run on the same machine (@var{host})
-as _GDBN__ itself.
+@var{target}. You may specify as many @samp{+target} options as you
+wish. Without this option, _GDBN__ is configured to debug programs that
+run on the same machine (@var{host}) as _GDBN__ itself.
+
+There is no convenient way to generate a list of all available targets.
@item @var{host} @dots{}
Configure _GDBN__ to run on each specified @var{host}. You may specify as
-many host names as you wish. To see a list of available hosts, execute
-@samp{ls xconfig} in the _GDBN__ source directory.
+many host names as you wish.
+
+There is no convenient way to generate a list of all available hosts.
@end table
@noindent
@code{configure} accepts other options, for compatibility with
-configuring other @sc{gnu} tools recursively; but these are the only
+configuring other GNU tools recursively; but these are the only
options that affect _GDBN__ or its supporting libraries.
-@node Formatting Manual, , configure Options, Installing _GDBN__
-@section Formatting this Manual
+@node Formatting Documentation, , configure Options, Installing _GDBN__
+@section Formatting the Documentation
-To format the _GDBN__ manual as an Info file, you need the @sc{gnu}
-@code{makeinfo} program. Once you have it, you can type
+@cindex _GDBN__ reference card
+@cindex reference card
+The _GDBN__ _GDB_VN__ release includes an already-formatted reference card,
+ready for printing on a PostScript printer, as @file{gdb-_GDB_VN__/gdb/refcard.ps}.
+It uses the most common PostScript fonts: the Times family, Courier, and
+Symbol. If you have a PostScript printer, you can print the reference
+card by just sending @file{refcard.ps} to the printer.
+
+The release also includes the online Info version of this manual already
+formatted: the main Info file is @file{gdb-_GDB_VN__/gdb/gdb.info}, and it
+refers to subordinate files matching @samp{gdb.info*} in the same
+directory.
+
+If you want to make these Info files yourself from the _GDBN__ manual's
+source, you need the GNU @code{makeinfo} program. Once you have it, you
+can type
@example
-cd @var{gnusrc}/gdb
+cd gdb-_GDB_VN__/gdb
make gdb.info
@end example
@noindent
to make the Info file.
-If you want to format and print copies of this manual, you need several
-things:
+If you want to format and print copies of the manual, you need several
+things:
@itemize @bullet
-@item
+@item
@TeX{}, the public domain typesetting program written by Donald Knuth,
must be installed on your system and available through your execution
path.
-@item
-@file{@var{gnusrc}/texinfo}: @TeX{} macros defining the @sc{gnu}
+@item
+@file{gdb-_GDB_VN__/texinfo}: @TeX{} macros defining the GNU
Documentation Format.
@item
-@emph{A @sc{dvi} output program.} @TeX{} doesn't actually make marks on
+@emph{A @sc{dvi} output program.} @TeX{} does not actually make marks on
paper; it produces output files called @sc{dvi} files. If your system
has @TeX{} installed, chances are it has a program for printing out
these files; one popular example is @code{dvips}, which can print
@noindent
Once you have these things, you can type
@example
-cd @var{gnusrc}/gdb
+cd gdb-_GDB_VN__/gdb
make gdb.dvi
@end example
@noindent
to format the text of this manual, and print it with the usual output
method for @TeX{} @sc{dvi} files at your site.
+If you want to print the reference card, but do not have a PostScript
+printer, or you want to use Computer Modern fonts instead,
+you can still print it if you have @TeX{}. Format the reference card by typing
+@example
+cd gdb-_GDB_VN__/gdb
+make refcard.dvi
+@end example
+@noindent
+
+The _GDBN__ reference card is designed to print in landscape mode on US
+``letter'' size paper; that is, on a sheet 11 inches wide by 8.5 inches
+high. You will need to specify this form of printing as an option to
+your @sc{dvi} output program.
+
+
@node Copying, Index, Installing _GDBN__, Top
@unnumbered GNU GENERAL PUBLIC LICENSE
@center Version 2, June 1991
the ``copyright'' line and a pointer to where the full notice is found.
@smallexample
-@var{one line to give the program's name and a brief idea of what it does.}
+@var{one line to give the program's name and an idea of what it does.}
Copyright (C) 19@var{yy} @var{name of author}
-This program is free software; you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 2 of the License, or
-(at your option) any later version.
+This program is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License
+as published by the Free Software Foundation; either version 2
+of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
-along with this program; if not, write to the Free Software
-Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+along with this program; if not, write to the
+Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.
@end smallexample
Also add information on how to contact you by electronic and paper mail.
@smallexample
Gnomovision version 69, Copyright (C) 19@var{yy} @var{name of author}
-Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
-This is free software, and you are welcome to redistribute it
-under certain conditions; type `show c' for details.
+Gnomovision comes with ABSOLUTELY NO WARRANTY; for details
+type `show w'. This is free software, and you are welcome
+to redistribute it under certain conditions; type `show c'
+for details.
@end smallexample
The hypothetical commands @samp{show w} and @samp{show c} should show
school, if any, to sign a ``copyright disclaimer'' for the program, if
necessary. Here is a sample; alter the names:
-@example
-Yoyodyne, Inc., hereby disclaims all copyright interest in the program
-`Gnomovision' (which makes passes at compilers) written by James Hacker.
+@smallexample
+Yoyodyne, Inc., hereby disclaims all copyright interest in
+the program `Gnomovision' (which makes passes at compilers)
+written by James Hacker.
@var{signature of Ty Coon}, 1 April 1989
Ty Coon, President of Vice
-@end example
+@end smallexample
This General Public License does not permit incorporating your program into
proprietary programs. If your program is a subroutine library, you may
\centerline{\fontname\tenrm,}
\centerline{with headings in {\bf\fontname\tenbf}}
\centerline{and examples in {\tt\fontname\tentt}.}
-\centerline{{\it\fontname\tenit\/} and}
+\centerline{{\it\fontname\tenit\/},}
+\centerline{{\bf\fontname\tenbf}, and}
\centerline{{\sl\fontname\tensl\/}}
\centerline{are used for emphasis.}\vfill}
\page\colophon
@end tex
@contents
projects / binutils.git / blobdiff