-_dnl__ -*-Texinfo-*-
+_dnl__ -*-Texinfo-*-
_dnl__ Copyright (c) 1988 1989 1990 1991 Free Software Foundation, Inc.
\input texinfo
@setfilename _GDBP__.info
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
+ m4 pretex.m4 none.m4 all.m4 gdb.texinfo >gdb-all.texinfo
_1__
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).
_fi__(0)
+_include__(gdbVN.m4)
@tex
\def\$#1${{#1}} % Kluge: collect RCS revision info without $...$
\xdef\manvers{\$Revision$} % For use in headers, footers too
@c
@syncodeindex ky cp
@c FOR UPDATES LEADING TO THIS DRAFT, GDB CHANGELOG CONSULTED BETWEEN:
-@c Sun May 19 05:36:59 1991 John Gilmore (gnu at cygint.cygnus.com)
+@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)
@ifinfo
This file documents the GNU debugger _GDBN__.
included in a translation approved by the Free Software Foundation
instead of in the original English.
@end ifinfo
-@smallbook
+@c @smallbook
@setchapternewpage odd
_if__(_GENERIC__)
-@settitle Using _GDBN__ (v4.0)
+@settitle Using _GDBN__ (<v>_GDB_VN__)
_fi__(_GENERIC__)
_if__(!_GENERIC__)
-@settitle Using _GDBN__ v4.0 (_HOST__)
+@settitle Using _GDBN__ <v>_GDB_VN__ (_HOST__)
_fi__(!_GENERIC__)
@iftex
@finalout
_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 May 1991
+@c @subtitle Third Edition---_GDBN__ version _GDB_VN__
+@subtitle _GDBN__ version _GDB_VN__
+@subtitle July 1991
@author{Richard M. Stallman@qquad @hfill Free Software Foundation}
@author{Roland H. Pesch@qquad @hfill Cygnus Support}
@page
@node Top, Summary, (dir), (dir)
@ifinfo
-This file describes version 4.0 of GDB, the GNU symbolic debugger.
+This file describes version _GDB_VN__ of GDB, the GNU symbolic debugger.
@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 in _GDBN__ version _GDB_VN__
+* 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
+* Starting _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
-* Stepping:: Stepping
-* Continuing:: Continuing
-* 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
+* Builtin 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 the 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.
_GDBN__ can do four main kinds of things (plus other things in support of
these) to help you catch bugs in the act:
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
@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__, 4.1, 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.
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
+GDB _GDB_VN__ 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.
contributed Intel 386 support. Jay Vosburgh contributed Symmetry
support.
-Rich Schaefer helped with support of SunOS shared libraries.
+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.
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 Binary File Descriptors (BFD) 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 .o's, archive
-libraries, or core dumps. BFD is available as a 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
+_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
+.o's, archive libraries, or core dumps. BFD is available as a
+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 and Ports
Compile-time configuration (to select a particular architecture and
-operating system) is much easier. The script @code{config.gdb} now
-handles specification of separate host and target configurations.
+operating system) is much easier. The script @code{configure} now
+allows you to configure _GDBN__ as either a native debugger or a
+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__ _GDB_VN__ can debug programs and core files that use SunOS shared
+libraries.
+
+@item Reference Card
+_GDBN__ _GDB_VN__ 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
@smallexample
$ @i{_GDBP__ m4}
-Reading symbol data from m4...done.
-(_GDBP__)
+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
(_GDBP__) @i{set width 70}
@end smallexample
-@noindent
+@noindent
Let's see how the @code{m4} builtin @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
@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}
@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}
@smallexample
(_GDBP__) @i{l}
533 xfree(rquote);
-534
+534
535 lquote = (lq == nil || *lq == '\0') ? def_lquote : xstrdup\
(lq);
536 rquote = (rq == nil || *rq == '\0') ? def_rquote : xstrdup\
(rq);
-537
+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.
@smallexample
(_GDBP__) @i{quit}
-
-$
_1__@end smallexample
@node Invocation, Commands, Sample Session, Top
@chapter Getting In and Out of _GDBN__
@menu
-* Starting _GDBN__:: Starting _GDBN__
-* Leaving _GDBN__:: Leaving _GDBN__
-* Shell Commands:: Shell Commands
+* Starting _GDBN__:: Starting _GDBN__
+* Leaving _GDBN__:: Leaving _GDBN__
+* Shell Commands:: Shell Commands
@end menu
@node Starting _GDBN__, Leaving _GDBN__, Invocation, Invocation
_GDBP__ program 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 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:
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__)
appropriate, and for examining pure data in conjunction with a core
dump.
-@item -se @var{file}
+@item -se=@var{file}
Read symbol table from file @var{file} and use it as the executable
file.
@end table
_if__(!_GENERIC__)
-@node Mode Options, i960-Nindy Remote, File Options, Starting _GDBN__
+@node Mode Options, Mode Options, File Options, Starting _GDBN__
_fi__(!_GENERIC__)
_if__(_GENERIC__)
@node Mode Options, , File Options, Starting _GDBN__
@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
(which is ordinarily issued whenever a program running under _GDBN__ control
terminates) is not issued when running in batch mode.
-@item -cd @var{directory}
+@item -cd=@var{directory}
Run _GDBN__ using @var{directory} as its working directory,
instead of the current directory.
Set the line speed (baud rate or bits per second) of any serial
interface used by _GDBN__ for remote debugging.
-@item -tty @var{device}
+@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.
@end table
@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
@chapter _GDBN__ Commands
@menu
-* Command Syntax:: Command Syntax
-* Help:: Getting Help
+* Command Syntax:: Command Syntax
+* Help:: Getting Help
@end menu
@node Command Syntax, Help, Commands, Commands
abbreviations are allowed; for example, @code{s} is specially defined as
equivalent to @code{step} even though there are other commands whose
names start with @code{s}. You can test abbreviations by using them as
-arguments to the @code{help} command (@pxref{Help}).
+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's 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.
@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
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}
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}
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.
+@c FIXME...the 'aux' file with a pageno the xref can't find it.
@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
@table @code
@kindex show version
+@cindex version number
@item show version
Show what version of _GDBN__ is running. You should include this
information in _GDBN__ bug-reports. If multiple versions of _GDBN__ are
@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
@item run
@itemx r
@kindex run
-Use the @code{run} command to start your program under _GDBN__.
+Use the @code{run} command to start your program under _GDBN__. You
+must first specify the program name
_if__(_VXWORKS__)
-Except on VxWorks, you
+(except on VxWorks)
_fi__(_VXWORKS__)
-_if__(!_VXWORKS__)
-You
-_fi__(!_VXWORKS__)
-must first specify the program name with an argument to _GDBN__
+with an argument to _GDBN__
(@pxref{Invocation}), or using the @code{file} or @code{exec-file}
-command (@pxref{Files}).@refill
+command (@pxref{Files}).
+@refill
@end table
On targets that support processes, @code{run} creates an inferior
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}.
+
+@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
+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
@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.
(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. You can use the string
-@samp{$cwd} to refer to whatever is the current working directory at the
-time _GDBN__ searches the path. @footnote{If you use @samp{.} instead,
-it refers to the directory where you executed the @code{path} command.
-_GDBN__ fills in the current path where needed in the @var{directory}
-argument, before adding it to the search path.}
+the front, so it will be searched sooner.
+
+You can use the string @samp{$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 document that, since repeating it would be a no-op.
@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 don't 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}.
-@item set environment @var{varname} @var{value}
-@itemx set environment @var{varname} = @var{value}
+@item set environment @var{varname} @r{[}=@r{]} @var{value}
@kindex set environment
Sets environment variable @var{varname} to @var{value}. The value
changes for your program only, not for _GDBN__ itself. @var{value} may
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
(@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.
@end table
@menu
-* Breakpoints:: Breakpoints, Watchpoints, and Exceptions
-* Stepping:: Stepping
-* Continuing:: Continuing
-* Signals:: Signals
+* Breakpoints:: Breakpoints, Watchpoints, and Exceptions
+* Continuing and Stepping:: Resuming Execution
+* Signals:: Signals
@end menu
-@node Breakpoints, Stepping, Stopping, Stopping
+@node Breakpoints, Continuing and Stepping, Stopping, Stopping
@section Breakpoints, Watchpoints, and Exceptions
@cindex breakpoints
no effect on the 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
@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. @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.
+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.
@item tbreak @var{args}
@kindex tbreak
@item rbreak @var{regex}
@kindex rbreak
@cindex regular expression
-@c FIXME: 2nd sentence below C++ only?
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
@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
+Some languages, such as GNU C++, implement exception handling. You can
+use _GDBN__ to examine what caused the program to raise an exception,
and to list the exceptions the program is prepared to handle at a
given point in time.
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}).
With a conditional breakpoint (@xref{Conditions}) that depends on the
value of @var{id}, you can stop your program when a specific exception
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{Stepping}.)
+@pxref{Continuing and Stepping}.)
@node Conditions, Break Commands, Disabling, Breakpoints
@subsection Break Conditions
The simplest sort of breakpoint breaks every time the 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 true.
+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}.
+
+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
+@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
your program. This can be useful, for example, to activate functions
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}).
+performing side effects when a breakpoint is reached
+(@pxref{Break Commands}).
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.
+watchpoint.
-@table @code
-@item condition @var{bnum} @var{expression}
-@kindex condition
+@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
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
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.
@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__
to nonsharable executables.
@end enumerate
-@node Stepping, Continuing, Breakpoints, Stopping
-@section Stepping
+@node Continuing and Stepping, Signals, Breakpoints, Stopping
+@section Continuing and Stepping
@cindex stepping
-@dfn{Stepping} means setting your program in motion for a limited time,
-so that control will return automatically to _GDBN__ after one line of
-code or one machine instruction. @footnote{Your program might stop even
-sooner, during stepping, since a signal may arrive before your program
-reaches the next source line. Also, since breakpoints are active during
-stepping, your program will stop for them even if it has not gone as far
-as the stepping command specifies.}
-
-A typical technique for using stepping is to put a breakpoint
+@cindex continuing
+@cindex resuming execution
+@dfn{Continuing} means resuming program execution until your program
+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, 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}.)
+
+@table @code
+@item continue @r{[}@var{ignore-count}@r{]}
+@kindex continue
+Resume program execution, at the address where the 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}).
+
+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.
+
+@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,
@kindex step
@kindex s
Continue running the program until control reaches a different source
-line, then stop it and return control to the debugger. This command is
+line, then stop it and return control to _GDBN__. This command is
abbreviated @code{s}.
-You may use the @code{step} command when control is within a function
-for which there is no debugging information. In that case, execution
-will proceed until control reaches a different function, or is about to
-return from this function.
+@quotation
+@emph{Warning:} If you use the @code{step} command while control is
+within a function that was compiled without debugging information,
+execution will proceed until control reaches another function.
+@end quotation
@item step @var{count}
Continue running as in @code{step}, but do so @var{count} times. If a
breakpoint is reached or a signal not related to stepping occurs before
@var{count} steps, stepping stops right away.
-@item next
+@item next @r{[}@var{count}@r{]}
@kindex next
@kindex n
-Continue to the next source line in the current stack frame. Similar to
-@code{step}, but any function calls appearing within the line of code
-are executed without stopping. Execution stops when control reaches a
-different line of code at the stack level which was executing when the
-@code{next} command was given. This command is abbreviated @code{n}.
+Continue to the next source line in the current (innermost) stack frame.
+Similar to @code{step}, but any function calls appearing within the line
+of code are executed without stopping. Execution stops when control
+reaches a different line of code at the stack level which was executing
+when the @code{next} command was given. This command is abbreviated
+@code{n}.
-An argument is a repeat count, as in @code{step}.
+An argument @var{count} is a repeat count, as for @code{step}.
@code{next} within a function that lacks debugging information acts like
@code{step}, but any function calls appearing within the code of the
@item finish
@kindex finish
-Continue running until just after the selected stack frame returns (or
-until there is some other reason to stop, such as a fatal signal or a
-breakpoint). Print the value returned by the selected stack frame (if
-any).
+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}).
stack frame.
@code{until} may produce somewhat counterintuitive results if the order
-of the source lines does not match the actual order of execution. For
+of machine code does not match the order of the source lines. For
example, in the following excerpt from a debugging session, the @code{f}
(@code{frame}) command shows that execution is stopped at line
@code{206}; yet when we use @code{until}, we get to line @code{195}:
@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
-In this case, (as for any C @code{for}-loop), the loop-step expression
-(here, @samp{argc > 0}) is executed @emph{after} the statements in the
-body of the loop, but is written before them. Therefore, the
-@code{until} command appeared to step back to the beginning of the loop
-when it advanced to this expression. However, it has not really gone to
-an earlier statement---not in terms of the actual machine code.
+This happened because, for execution efficiency, the compiler had
+generated code for the loop closure test at the end, rather than the
+start, of the loop---even though the test in a C @code{for}-loop is
+written before the body of the loop. The @code{until} command appeared
+to step back to the beginning of the loop when it advanced to this
+expression; however, it has not really gone to an earlier
+statement---not in terms of the actual machine code.
@code{until} with no argument works by means of single
instruction stepping, and hence is slower than @code{until} with an
@item until @var{location}
@item u @var{location}
Continue running the program until either the specified location is
-reached, or the current (innermost) 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.
+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.
@item stepi
@itemx si
An argument is a repeat count, as in @code{next}.
@end table
-The @code{continue} command can be used after stepping to resume execution
-until the next breakpoint or signal.
-
-@node Continuing, Signals, Stepping, Stopping
-@section Continuing
-
-After your program stops, most likely you will want it to run some more if
-the bug you are looking for has not happened yet.
-
-@table @code
-@item continue
-@kindex continue
-Continue running the program at the place where it stopped.
-@end table
-
-If the program stopped at a breakpoint, the place to continue running
-is the address of the breakpoint. You might expect that continuing would
-just stop at the same breakpoint immediately. In fact, @code{continue}
-takes special care to prevent that from happening. You do not need
-to disable the breakpoint to proceed through it after stopping there.
-You can, however, specify an ignore-count for the breakpoint that the
-program stopped at, by means of an argument to the @code{continue} command.
-@xref{Conditions}.
-
-If the program stopped because of a signal other than @code{SIGINT} or
-@code{SIGTRAP}, continuing will cause the program to see that signal.
-You may not want this to happen. For example, if the 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}. You can
-also act in advance to control what signals your program will see, using
-the @code{handle} command (@pxref{Signals}).
-@node Signals, , Continuing, Stopping
+@node Signals, , Continuing and Stepping, Stopping
@section Signals
@cindex signals
You can also use the @code{signal} command to prevent the 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. @xref{Signaling}.
+or to give it any signal at any time. For example, if the 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}.
@node Stack, Source, Stopping, Top
@chapter Examining the Stack
When the 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}).
@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
addition, this can be useful when the 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
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
@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
use Emacs facilities to view source; @pxref{Emacs}.
@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
+as part of displaying a stack frame (@pxref{Stack}), this prints
lines centered around that line.
@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.
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. 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 working directory.
-@footnote{@samp{$cwd} is not the same as @samp{.}---the former tracks
-the current working directory as it changes during your _GDBN__ session,
-while the latter is immediately expanded to the current directory at the
-time you add an entry to the source path.}
+path; this moves it forward, so it will be searched sooner.
+
+You can use the string @samp{$cdir} to refer to the compilation
+directory (if one is recorded), and @samp{$cwd} to refer to the current
+working directory. @samp{$cwd} is not the same as @samp{.}---the former
+tracks the current working directory as it changes during your _GDBN__
+session, while the latter is immediately expanded to the current
+directory at the time you add an entry to the source path.
@item directory
Reset the source path to empty again. This requires confirmation.
Line 926 of "builtin.c" starts at pc 0x63e4 and ends at 0x6404.
@end smallexample
-@kindex $_
+@cindex @code{$_} 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
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
@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}). You type
@example
print @var{exp}
@end example
@noindent
-where @var{exp} is any valid expression (in the source language), and
+where @var{exp} is an expression (in the source language), and
the value of @var{exp} is printed in a format appropriate to its data
type.
It examines data in memory at a specified address and prints it in a
specified format. @xref{Memory}.
+If you're 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
@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
+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,
+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
+through that group of instructions, local variable definitions may be
+gone.
+@end quotation
@node Arrays, Output formats, Variables, Data
@section Artificial Arrays
Artificial arrays most often appear in expressions via the value history
(@pxref{Value History}), after printing one out.)
+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:
+@example
+set $i = 0
+p dtab[$i++]->fv
+@key{RET}
+@key{RET}
+@dots{}
+@end example
+
@node Output formats, Memory, Arrays, Data
@section Output formats
@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).
-@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}.
+Giant words (eight bytes).
@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 $__
-The addresses and contents printed by the @code{x} command are not put
+Since the letters indicating unit sizes are all distinct from the
+letters specifying output formats, you don't have to remember whether
+unit size or format comes first; either order will work. The output
+specifications @samp{4xw} and @samp{4wx} mean exactly the same thing.
+(However, the count @var{n} must come first; @samp{wx4} will not work.)
+
+Even though the unit size @var{u} is ignored for the formats @samp{s}
+and @samp{i}, you might still want to use a count @var{n}; for example,
+@samp{3i} specifies that you want to see three machine instructions,
+including any operands. The command @code{disassemble} gives an
+alternative way of inspecting machine instructions; @pxref{Machine
+Code}.
+
+All the defaults for the arguments to @code{x} are designed to make it
+easy to continue scanning memory with minimal specifications each time
+you use @code{x}. For example, after you've inspected three machine
+instructions with @samp{x/3i @var{addr}}, you can inspect the next seven
+with just @samp{x/7}. If you use @key{RET} to repeat the @code{x} command,
+the repeat count @var{n} is used again; the other arguments default as
+for successive uses of @code{x}.
+
+@cindex @code{$_}, @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
@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
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{$_}
to that address; these commands include @code{info line} and @code{info
-breakpoint}.
+breakpoint}. The type of @code{$_} 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}
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 the program's
+native language, and allowing _GDBN__ to output values in a manner
+consistent with the syntax of the 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;
-@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;
-@}
+print a = b + c
@end example
-@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.
+@noindent
+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 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!
+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.
-@item info functions
-@kindex info functions
-Print the names and data types of all defined functions.
+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 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}.
+@node Show, Checks, Setting, Languages
+@section Displaying the language
-@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).
+The following commands will help you find out which language is the
+working language, and also what language source files were written in.
-@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}.
+@kindex show language
+@kindex info frame
+@kindex info source
+@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 the program.
+@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.
-@ignore
-This was never implemented.
-@item info methods
-@itemx info methods @var{regexp}
-@kindex info methods
-The @code{info methods} command permits the user to examine all defined
-methods within C++ program, or (with the @var{regexp} argument) a
-specific set of methods found in the various C++ classes. Many
-C++ classes provide a large number of methods. Thus, the output
-from the @code{ptype} command can be overwhelming and hard to use. The
-@code{info-methods} command filters the methods, printing only those
-which match the regular-expression @var{regexp}.
-@end ignore
+@item info source
+Among the other information listed here (@pxref{Symbols,,Examining the
+Symbol Table}) is the source language of this source file.
-@item printsyms @var{filename}
-@kindex printsyms
-Write a complete dump of the debugger's symbol data into the
-file @var{filename}.
@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
-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.
+@node Checks, Support, Show, Languages
+@section Type and range Checking
-For example, you can store new values into variables or memory
-locations, give the program a signal, restart it at a different address,
-or even return prematurely from a function to its caller.
+@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 the 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
+the source language of the program being debugged.
+@xref{Support,,Supported Languages}, for the default settings
+of supported languages.
@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
+* Type Checking:: An overview of type checking
+* Range Checking:: An overview of range checking
@end menu
-@node Assignment, Jumping, Altering, Altering
-@section Assignment to Variables
+@cindex type checking
+@cindex checks, type
+@node Type Checking, Range Checking, Checks, Checks
+@subsection An overview of type checking
-@cindex assignment
-@cindex setting variables
-To alter the value of a variable, evaluate an assignment expression.
-@xref{Expressions}. For example,
+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
-print x=4
+1 + 2 @result{} 3
+@error{} 1 + 2.3
@end example
-@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__.
+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}.
+
+@cindex C++ exception handling
+@item catch @var{exceptions}
+@itemx info catch
+Debug C++ exception handling using these commands. @xref{Exception Handling}.
+
+@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
+* Builtin 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, Builtin 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 builtins
+@node Builtin 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, Builtin 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 builtin 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 builtin 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 delcared
+identifier within the 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 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}).
+
+@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}
+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
+
+@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 the 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
+The @code{info methods} command permits the user to examine all defined
+methods within C++ program, or (with the @var{regexp} argument) a
+specific set of methods found in the various C++ classes. Many
+C++ classes provide a large number of methods. Thus, the output
+from the @code{ptype} command can be overwhelming and hard to use. The
+@code{info-methods} command filters the methods, printing only those
+which match the regular-expression @var{regexp}.
+@end ignore
+
+@item printsyms @var{filename}
+@itemx printpsyms @var{filename}
+@kindex printsyms
+@cindex symbol dump
+@kindex printsyms
+@cindex partial symbol dump
+Write a dump of debugging symbol data into the file @var{filename}.
+These commands are useful for debugging 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 find out
+which files these are using the command @code{info sources}. On the
+other hand, 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}.
+
+@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
+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,
+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
+* Patching:: Patching your Program
+@end menu
+
+@node Assignment, Jumping, Altering, Altering
+@section Assignment to Variables
+
+@cindex assignment
+@cindex setting variables
+To alter the value of a variable, evaluate an assignment expression.
+@xref{Expressions}. For example,
+
+@example
+print x=4
+@end example
+
+@noindent
+would store the value 4 into the variable @code{x}, and then print the
+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{}@}}
@noindent
causes the next @code{continue} command or stepping command to execute at
address 0x485, rather than at the address where the program stopped.
-@xref{Stepping}.
+@xref{Continuing and Stepping}.
The most common occasion to use the @code{jump} command is to back up,
perhaps with more breakpoints set, over a portion of a program that has
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
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{Stepping})
-resumes execution until the selected stack frame returns naturally.
+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
@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 the program.
@item symbol-file @var{filename}
@kindex symbol-file
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're 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 (@xref{Messages/Warnings}).
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
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
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
-The debugger 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 the 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 the 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}). To specify as a target
+a process that's already running, use the @code{attach} command
+(@pxref{Attach}).
@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.
_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,
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
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
@code{symbol-file}).
@c The following is the right way to do it, but emacs 18.55 doesn't 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}).
@end ignore
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
Displays state of confirmation requests.
@end table
+@c FIXME this doesn't 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're 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
+Don't replace symbol definitions when re-encountering object files of
+the same name. This is the default state; if you're 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
user-defined commands and command files.
@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
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
@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
commands and input them again; you can even use parts of the output
in this way.
-All the facilities of Emacs' Shell mode are available for this purpose.
+All the facilities of Emacs' Shell mode are available for interacting
+with your program. In particular, you can send signals the usual
+way---for example, @kbd{C-c C-c} for an interrupt, @kbd{C-c C-z} for a
+stop.
@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
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
@node Bug Reporting, , Bug Criteria, _GDBN__ Bugs
@section How to Report Bugs
@cindex Bug Reports
-@cindex Compiler Bugs, Reporting
+@cindex _GDBN__ Bugs, Reporting
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.
@samp{help-gdb}, or to any newsgroups.} Most users of _GDBN__ do not want to
receive bug reports. Those that do, have arranged to receive @samp{bug-gdb}.
-The mailing list @samp{bug-gdb} has a newsgroup which serves as a
-repeater. The mailing list and the newsgroup carry exactly the same
-messages. Often people think of posting bug reports to the newsgroup
-instead of mailing them. This appears to work, but it has one problem
-which can be crucial: a newsgroup posting often lacks a mail path
-back to the sender. Thus, if we need to ask for more information, we
-may be unable to reach you. For this reason, it is better to send bug
-reports to the mailing list.
+The mailing list @samp{bug-gdb} has a newsgroup @samp{gnu.gdb.bug} which
+serves as a repeater. The mailing list and the newsgroup carry exactly
+the same messages. Often people think of posting bug reports to the
+newsgroup instead of mailing them. This appears to work, but it has one
+problem which can be crucial: a newsgroup posting often lacks a mail
+path back to the sender. Thus, if we need to ask for more information,
+we may be unable to reach you. For this reason, it is better to send
+bug reports to the mailing list.
As a last resort, send bug reports on paper to:
@example
GNU Debugger Bugs
+Free Software Foundation
545 Tech Square
Cambridge, MA 02139
@end example
@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,
report the bug anyway and send us the entire test case you used.
@end itemize
@iftex
-@include rdl-apps.texinfo
+@include rdl-apps.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
@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 ]
+@example
+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]
+@end example
@end ifinfo
@tex
@cindex configuring _GDBN__
@cindex installation
-The script @code{config.gdb} automates the process of preparing _GDBN__
-for installation; you can then use @code{make} to actually build it.
-The best way to build _GDBN__ is in a subdirectory that records the
-configuration options used; this gives you a clean way of building
-_GDBN__ binaries with several different configuration options.
-@code{config.gdb} doesn't depend on this---it's just a good habit. For
-example, assuming the _GDBN__ source is in a directory called
-``@code{gdb-4.0}'':
+_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 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 gdb-_GDB_VN__/bfd
+source for the Binary File Descriptor Library
+
+@item gdb-_GDB_VN__/include
+GNU include files
+
+@item gdb-_GDB_VN__/libiberty
+source for the @samp{-liberty} free software library
+
+@item gdb-_GDB_VN__/readline
+source for the GNU command-line interface
+@end table
+@noindent
+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 gdb-_GDB_VN__
+./configure @var{host}
+make
+@end example
+@noindent
+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.
+
+@code{configure} is a Bourne-shell (@code{/bin/sh}) script; if your
+system doesn't 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
+cd gdb-_GDB_VN__/bfd
+../configure @var{host}
+@end example
+
+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
+@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
+* 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, Config Names, Installing _GDBN__, Installing _GDBN__
+@section Configuration Subdirectories
+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's 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
-cd gdb-4.0
-mkdir =sun3os4
-cd =sun3os4
-../config.gdb sun3os4
+@group
+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{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
+
+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 gdb-_GDB_VN__
+configure sun4 +target=vxworks960
+@end example
+@noindent
+creates the following directories:
+@smallexample
+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 smallexample
+
+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.
+
+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.
+
+@ifinfo
+@example
+
+ARCHITECTURE VENDOR OS prefix
+------------+------------+-------------
+ | |
+ 580 | altos | aix*
+ a29k | amd | amigados
+ alliant | amdahl | aout
+ arm | aout | bout
+ c1 | apollo | bsd*
+ c2 | att | coff
+ cray2 | bcs | ctix*
+ h8300 | bout | dgux*
+ i386 | bull | dynix*
+ i860 | cbm | ebmon
+ i960 | coff | esix*
+ m68000 | convergent | hds
+ m68k | convex | hpux*
+ m88k | cray | irix*
+ mips | dec | isc*
+ ns32k | encore | kern
+ pyramid | gould | mach*
+ romp | hitachi | msdos*
+ rs6000 | hp | newsos*
+ sparc | ibm | nindy*
+ tahoe | intel | osf*
+ tron | isi | sco*
+ vax | little | sunos*
+ xmp | mips | svr4
+ ymp | motorola | sym*
+ | ncr | sysv*
+ | next | ultrix*
+ | nyu | unicos*
+ | sco | unos*
+ | sequent | uts
+ | sgi | v88r*
+ | sony | vms*
+ | sun | vxworks*
+ | unicom |
+ | utek |
+ | wrs |
+
+@end example
+@quotation
+@emph{Warning:} Many combinations of architecture, vendor, and OS are
+untested.
+@end quotation
+@end ifinfo
+@c FIXME: this table is probably screwed in @smallbook. Try setting
+@c FIXME...smallbook fonts?
+@tex
+%\vskip\parskip
+\advance\baselineskip -1pt
+% TERRIBLE KLUGE ABOVE makes table fit on one page (large format, prob
+% not smallbook). FIXME Reformat table for next time!!
+\vskip \baselineskip
+\halign{\hskip\parindent\tt #\hfil &\qquad#&\tt #\hfil &\qquad#&\tt
+#\hfil &\qquad\qquad\it #\hfil\cr
+{\bf Architecture} &&{\bf Vendor} &&{\bf OS prefix}\cr
+\multispan5\hrulefill\cr
+ 580 && altos && aix* \cr
+ a29k && amd && amigados \cr
+ alliant && amdahl && aout \cr
+ arm && aout && bout \cr
+ c1 && apollo && bsd* \cr
+ c2 && att && coff \cr
+ cray2 && bcs && ctix* \cr
+ h8300 && bout && dgux* \cr
+ i386 && bull && dynix* \cr
+ i860 && cbm && ebmon &Warning: \cr
+ i960 && coff && esix* &Many combinations \cr
+ m68000 && convergent && hds &of architecture, vendor \cr
+ m68k && convex && hpux* &and OS are untested. \cr
+ m88k && cray && irix* \cr
+ mips && dec && isc* \cr
+ ns32k && encore && kern \cr
+ pyramid && gould && mach* \cr
+ romp && hitachi && msdos* \cr
+ rs6000 && hp && newsos* \cr
+ sparc && ibm && nindy* \cr
+ tahoe && intel && osf* \cr
+ tron && isi && sco* \cr
+ vax && little && sunos* \cr
+ xmp && mips && svr4 \cr
+ ymp && motorola && sym* \cr
+ && ncr && sysv* \cr
+ && next && ultrix* \cr
+ && nyu && unicos* \cr
+ && sco && unos* \cr
+ && sequent && uts \cr
+ && sgi && v88r* \cr
+ && sony && vms* \cr
+ && sun && vxworks* \cr
+ && unicom && \cr
+ && utek && \cr
+ && wrs && \cr
+}
+@end tex
+
+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{[}+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
-will install _GDBN__ on a Sun 3 running SunOS 4.
+You may introduce options with the character @samp{-} rather than
+@samp{+} if you prefer; but you may abbreviate option names if you use
+@samp{+}.
@table @code
-@kindex config.gdb
-@item config.gdb @var{machine}
-@itemx config.gdb -srcdir=@var{dir} @var{machine}
-This is the most usual way of configuring _GDBN__; to debug programs running
-on the same machine as _GDBN__ itself. If you wish to build the _GDBN__ binaries
-in a completely different directory from the sources, specify a path to
-the source directory using the @samp{-srcdir} option.
-
-@item config.gdb -host
-@cindex host environments
-Display a list of supported host environments for _GDBN__.
-
-@item config.gdb @var{host} @var{target}
-@itemx config.gdb -srcdir=@var{dir} @var{host} @var{target}
-@cindex cross-debugging
-_GDBN__ can also be used as a cross-debugger, running on a machine of one
-type while debugging a program running on a machine of another type.
-You configure it this way by specifying first the @var{host}, then the
-@var{target} environment on the @code{config.gdb} argument list; the
-@var{host} is where _GDBN__ runs, and the @var{target} is where your program
-runs. @xref{Remote}. Again, you can use @samp{-srcdir} to specify a
-path to the _GDBN__ source.
-
-@item config.gdb -target
-@cindex target environments
-Display a list of supported target environments for _GDBN__.
+@item +destdir=@var{dir}
+@var{dir} is an installation directory @emph{path prefix}. After you
+configure with this option, @code{make install} will install _GDBN__ as
+@file{@var{dir}/bin/_GDBP__}, and the libraries in @file{@var{dir}/lib}.
+If you specify @samp{+destdir=/usr/local}, for example, @code{make
+install} creates @file{/usr/local/bin/gdb}.@refill
+
+@item +subdirs
+Write configuration specific files in subdirectories of the form
+@example
+H-@var{host}/T-@var{target}
+@end example
+@noindent
+(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 that the other arguments specify.
+
+@c This doesn't 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{target} @dots{}
+Configure _GDBN__ for cross-debugging programs running on each specified
+@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.
+
+There is no convenient way to generate a list of all available hosts.
@end table
-@node Copying, Index, Installing _GDBN__, Top
-@appendix Copying GDB
-@c this is an attempt to kluge around what may be a bug in texinfo;
-@c @xrefs to this node came out pointing several pages further down when
-@c the @node was immediately followed by @unnumbered.
-@c While we're at it, might as well give an Appendix heading that
-@c matches RMS' preferred nodename "Copying".
+@noindent
+@code{configure} accepts other options, for compatibility with
+configuring other GNU tools recursively; but these are the only
+options that affect _GDBN__ or its supporting libraries.
+
+@node Formatting Documentation, , configure Options, Installing _GDBN__
+@section Formatting the Documentation
+
+@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 gdb-_GDB_VN__/gdb
+make gdb.info
+@end example
+@noindent
+to make the Info file.
+
+If you want to format and print copies of the manual, you need several
+things:
+@itemize @bullet
+@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{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
+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
+@sc{dvi} files on PostScript printers.
+@end itemize
+@noindent
+Once you have these things, you can type
+@example
+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 don't 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 1, February 1989
+@center Version 2, June 1991
@display
-Copyright @copyright{} 1989 Free Software Foundation, Inc.
+Copyright @copyright{} 1989, 1991 Free Software Foundation, Inc.
675 Mass Ave, Cambridge, MA 02139, USA
Everyone is permitted to copy and distribute verbatim copies
@unnumberedsec Preamble
- The license agreements of most software companies try to keep users
-at the mercy of those companies. By contrast, our General Public
+ The licenses for most software are designed to take away your
+freedom to share and change it. By contrast, the GNU General Public
License is intended to guarantee your freedom to share and change free
-software---to make sure the software is free for all its users. The
-General Public License applies to the Free Software Foundation's
-software and to any other program whose authors commit to using it.
-You can use it for your programs, too.
+software---to make sure the software is free for all its users. This
+General Public License applies to most of the Free Software
+Foundation's software and to any other program whose authors commit to
+using it. (Some other Free Software Foundation software is covered by
+the GNU Library General Public License instead.) You can apply it to
+your programs, too.
When we speak of free software, we are referring to freedom, not
-price. Specifically, the General Public License is designed to make
-sure that you have the freedom to give away or sell copies of free
-software, that you receive source code or can get it if you want it,
-that you can change the software or use pieces of it in new free
-programs; and that you know you can do these things.
+price. Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+this service if you wish), that you receive source code or can get it
+if you want it, that you can change the software or use pieces of it
+in new free programs; and that you know you can do these things.
To protect your rights, we need to make restrictions that forbid
anyone to deny you these rights or to ask you to surrender the rights.
These restrictions translate to certain responsibilities for you if you
distribute copies of the software, or if you modify it.
- For example, if you distribute copies of a such a program, whether
+ For example, if you distribute copies of such a program, whether
gratis or for a fee, you must give the recipients all the rights that
you have. You must make sure that they, too, receive or can get the
-source code. And you must tell them their rights.
+source code. And you must show them these terms so they know their
+rights.
We protect your rights with two steps: (1) copyright the software, and
(2) offer you this license which gives you legal permission to copy,
that any problems introduced by others will not reflect on the original
authors' reputations.
+ Finally, any free program is threatened constantly by software
+patents. We wish to avoid the danger that redistributors of a free
+program will individually obtain patent licenses, in effect making the
+program proprietary. To prevent this, we have made it clear that any
+patent must be licensed for everyone's free use or not licensed at all.
+
The precise terms and conditions for copying, distribution and
modification follow.
@iftex
-@unnumberedsec TERMS AND CONDITIONS
+@unnumberedsec TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
@end iftex
@ifinfo
-@center TERMS AND CONDITIONS
+@center TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
@end ifinfo
@enumerate
@item
-This License Agreement applies to any program or other work which
-contains a notice placed by the copyright holder saying it may be
-distributed under the terms of this General Public License. The
-``Program'', below, refers to any such program or work, and a ``work based
-on the Program'' means either the Program or any work containing the
-Program or a portion of it, either verbatim or with modifications. Each
-licensee is addressed as ``you''.
+This License applies to any program or other work which contains
+a notice placed by the copyright holder saying it may be distributed
+under the terms of this General Public License. The ``Program'', below,
+refers to any such program or work, and a ``work based on the Program''
+means either the Program or any derivative work under copyright law:
+that is to say, a work containing the Program or a portion of it,
+either verbatim or with modifications and/or translated into another
+language. (Hereinafter, translation is included without limitation in
+the term ``modification''.) Each licensee is addressed as ``you''.
+
+Activities other than copying, distribution and modification are not
+covered by this License; they are outside its scope. The act of
+running the Program is not restricted, and the output from the Program
+is covered only if its contents constitute a work based on the
+Program (independent of having been made by running the Program).
+Whether that is true depends on what the Program does.
@item
-You may copy and distribute verbatim copies of the Program's source
-code as you receive it, in any medium, provided that you conspicuously and
-appropriately publish on each copy an appropriate copyright notice and
-disclaimer of warranty; keep intact all the notices that refer to this
-General Public License and to the absence of any warranty; and give any
-other recipients of the Program a copy of this General Public License
-along with the Program. You may charge a fee for the physical act of
-transferring a copy.
+You may copy and distribute verbatim copies of the Program's
+source code as you receive it, in any medium, provided that you
+conspicuously and appropriately publish on each copy an appropriate
+copyright notice and disclaimer of warranty; keep intact all the
+notices that refer to this License and to the absence of any warranty;
+and give any other recipients of the Program a copy of this License
+along with the Program.
-@item
-You may modify your copy or copies of the Program or any portion of
-it, and copy and distribute such modifications under the terms of Paragraph
-1 above, provided that you also do the following:
+You may charge a fee for the physical act of transferring a copy, and
+you may at your option offer warranty protection in exchange for a fee.
-@itemize @bullet
@item
-cause the modified files to carry prominent notices stating that
-you changed the files and the date of any change; and
+You may modify your copy or copies of the Program or any portion
+of it, thus forming a work based on the Program, and copy and
+distribute such modifications or work under the terms of Section 1
+above, provided that you also meet all of these conditions:
+@alphaenumerate
@item
-cause the whole of any work that you distribute or publish, that
-in whole or in part contains the Program or any part thereof, either
-with or without modifications, to be licensed at no charge to all
-third parties under the terms of this General Public License (except
-that you may choose to grant warranty protection to some or all
-third parties, at your option).
+You must cause the modified files to carry prominent notices
+stating that you changed the files and the date of any change.
@item
-If the modified program normally reads commands interactively when
-run, you must cause it, when started running for such interactive use
-in the simplest and most usual way, to print or display an
-announcement including an appropriate copyright notice and a notice
-that there is no warranty (or else, saying that you provide a
-warranty) and that users may redistribute the program under these
-conditions, and telling the user how to view a copy of this General
-Public License.
+You must cause any work that you distribute or publish, that in
+whole or in part contains or is derived from the Program or any
+part thereof, to be licensed as a whole at no charge to all third
+parties under the terms of this License.
@item
-You may charge a fee for the physical act of transferring a
-copy, and you may at your option offer warranty protection in
-exchange for a fee.
-@end itemize
-
-Mere aggregation of another independent work with the Program (or its
-derivative) on a volume of a storage or distribution medium does not bring
-the other work under the scope of these terms.
+If the modified program normally reads commands interactively
+when run, you must cause it, when started running for such
+interactive use in the most ordinary way, to print or display an
+announcement including an appropriate copyright notice and a
+notice that there is no warranty (or else, saying that you provide
+a warranty) and that users may redistribute the program under
+these conditions, and telling the user how to view a copy of this
+License. (Exception: if the Program itself is interactive but
+does not normally print such an announcement, your work based on
+the Program is not required to print an announcement.)
+@end alphaenumerate
+
+These requirements apply to the modified work as a whole. If
+identifiable sections of that work are not derived from the Program,
+and can be reasonably considered independent and separate works in
+themselves, then this License, and its terms, do not apply to those
+sections when you distribute them as separate works. But when you
+distribute the same sections as part of a whole which is a work based
+on the Program, the distribution of the whole must be on the terms of
+this License, whose permissions for other licensees extend to the
+entire whole, and thus to each and every part regardless of who wrote it.
+
+Thus, it is not the intent of this section to claim rights or contest
+your rights to work written entirely by you; rather, the intent is to
+exercise the right to control the distribution of derivative or
+collective works based on the Program.
+
+In addition, mere aggregation of another work not based on the Program
+with the Program (or with a work based on the Program) on a volume of
+a storage or distribution medium does not bring the other work under
+the scope of this License.
@item
-You may copy and distribute the Program (or a portion or derivative of
-it, under Paragraph 2) in object code or executable form under the terms of
-Paragraphs 1 and 2 above provided that you also do one of the following:
+You may copy and distribute the Program (or a work based on it,
+under Section 2) in object code or executable form under the terms of
+Sections 1 and 2 above provided that you also do one of the following:
-@itemize @bullet
+@alphaenumerate
@item
-accompany it with the complete corresponding machine-readable
-source code, which must be distributed under the terms of
-Paragraphs 1 and 2 above; or,
+Accompany it with the complete corresponding machine-readable
+source code, which must be distributed under the terms of Sections
+1 and 2 above on a medium customarily used for software interchange; or,
@item
-accompany it with a written offer, valid for at least three
-years, to give any third party free (except for a nominal charge
-for the cost of distribution) a complete machine-readable copy of the
-corresponding source code, to be distributed under the terms of
-Paragraphs 1 and 2 above; or,
+Accompany it with a written offer, valid for at least three
+years, to give any third party, for a charge no more than your
+cost of physically performing source distribution, a complete
+machine-readable copy of the corresponding source code, to be
+distributed under the terms of Sections 1 and 2 above on a medium
+customarily used for software interchange; or,
@item
-accompany it with the information you received as to where the
-corresponding source code may be obtained. (This alternative is
+Accompany it with the information you received as to the offer
+to distribute corresponding source code. (This alternative is
allowed only for noncommercial distribution and only if you
-received the program in object code or executable form alone.)
-@end itemize
-
-Source code for a work means the preferred form of the work for making
-modifications to it. For an executable file, complete source code means
-all the source code for all modules it contains; but, as a special
-exception, it need not include source code for modules which are standard
-libraries that accompany the operating system on which the executable
-file runs, or for standard header files or definitions files that
-accompany that operating system.
+received the program in object code or executable form with such
+an offer, in accord with Subsection b above.)
+@end alphaenumerate
+
+The source code for a work means the preferred form of the work for
+making modifications to it. For an executable work, complete source
+code means all the source code for all modules it contains, plus any
+associated interface definition files, plus the scripts used to
+control compilation and installation of the executable. However, as a
+special exception, the source code distributed need not include
+anything that is normally distributed (in either source or binary
+form) with the major components (compiler, kernel, and so on) of the
+operating system on which the executable runs, unless that component
+itself accompanies the executable.
+
+If distribution of executable or object code is made by offering
+access to copy from a designated place, then offering equivalent
+access to copy the source code from the same place counts as
+distribution of the source code, even though third parties are not
+compelled to copy the source along with the object code.
@item
-You may not copy, modify, sublicense, distribute or transfer the
-Program except as expressly provided under this General Public License.
-Any attempt otherwise to copy, modify, sublicense, distribute or transfer
-the Program is void, and will automatically terminate your rights to use
-the Program under this License. However, parties who have received
-copies, or rights to use copies, from you under this General Public
-License will not have their licenses terminated so long as such parties
-remain in full compliance.
+You may not copy, modify, sublicense, or distribute the Program
+except as expressly provided under this License. Any attempt
+otherwise to copy, modify, sublicense or distribute the Program is
+void, and will automatically terminate your rights under this License.
+However, parties who have received copies, or rights, from you under
+this License will not have their licenses terminated so long as such
+parties remain in full compliance.
@item
-By copying, distributing or modifying the Program (or any work based
-on the Program) you indicate your acceptance of this license to do so,
-and all its terms and conditions.
+You are not required to accept this License, since you have not
+signed it. However, nothing else grants you permission to modify or
+distribute the Program or its derivative works. These actions are
+prohibited by law if you do not accept this License. Therefore, by
+modifying or distributing the Program (or any work based on the
+Program), you indicate your acceptance of this License to do so, and
+all its terms and conditions for copying, distributing or modifying
+the Program or works based on it.
@item
Each time you redistribute the Program (or any work based on the
-Program), the recipient automatically receives a license from the original
-licensor to copy, distribute or modify the Program subject to these
-terms and conditions. You may not impose any further restrictions on the
-recipients' exercise of the rights granted herein.
+Program), the recipient automatically receives a license from the
+original licensor to copy, distribute or modify the Program subject to
+these terms and conditions. You may not impose any further
+restrictions on the recipients' exercise of the rights granted herein.
+You are not responsible for enforcing compliance by third parties to
+this License.
+
+@item
+If, as a consequence of a court judgment or allegation of patent
+infringement or for any other reason (not limited to patent issues),
+conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License. If you cannot
+distribute so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you
+may not distribute the Program at all. For example, if a patent
+license would not permit royalty-free redistribution of the Program by
+all those who receive copies directly or indirectly through you, then
+the only way you could satisfy both it and this License would be to
+refrain entirely from distribution of the Program.
+
+If any portion of this section is held invalid or unenforceable under
+any particular circumstance, the balance of the section is intended to
+apply and the section as a whole is intended to apply in other
+circumstances.
+
+It is not the purpose of this section to induce you to infringe any
+patents or other property right claims or to contest validity of any
+such claims; this section has the sole purpose of protecting the
+integrity of the free software distribution system, which is
+implemented by public license practices. Many people have made
+generous contributions to the wide range of software distributed
+through that system in reliance on consistent application of that
+system; it is up to the author/donor to decide if he or she is willing
+to distribute software through any other system and a licensee cannot
+impose that choice.
+
+This section is intended to make thoroughly clear what is believed to
+be a consequence of the rest of this License.
+
+@item
+If the distribution and/or use of the Program is restricted in
+certain countries either by patents or by copyrighted interfaces, the
+original copyright holder who places the Program under this License
+may add an explicit geographical distribution limitation excluding
+those countries, so that distribution is permitted only in or among
+countries not thus excluded. In such case, this License incorporates
+the limitation as if written in the body of this License.
@item
The Free Software Foundation may publish revised and/or new versions
address new problems or concerns.
Each version is given a distinguishing version number. If the Program
-specifies a version number of the license which applies to it and ``any
+specifies a version number of this License which applies to it and ``any
later version'', you have the option of following the terms and conditions
either of that version or of any later version published by the Free
Software Foundation. If the Program does not specify a version number of
-the license, you may choose any version ever published by the Free Software
+this License, you may choose any version ever published by the Free Software
Foundation.
@item
REPAIR OR CORRECTION.
@item
-IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL
-ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
+IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
-INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES
-ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT
-LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES
-SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE
-WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN
-ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
+INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
+OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
+TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
+YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
+PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGES.
@end enumerate
@iftex
@unnumberedsec Applying These Terms to Your New Programs
If you develop a new program, and you want it to be of the greatest
-possible use to humanity, the best way to achieve this is to make it
-free software which everyone can redistribute and change under these
-terms.
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
- To do so, attach the following notices to the program. It is safest to
-attach them to the start of each source file to most effectively convey
-the exclusion of warranty; and each file should have at least the
-``copyright'' line and a pointer to where the full notice is found.
+ To do so, attach the following notices to the program. It is safest
+to attach them to the start of each source file to most effectively
+convey the exclusion of warranty; and each file should have at least
+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.}
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 1, or (at your option)
-any later version.
+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
under certain conditions; type `show c' for details.
@end smallexample
-The hypothetical commands `show w' and `show c' should show the
-appropriate parts of the General Public License. Of course, the
-commands you use may be called something other than `show w' and `show
-c'; they could even be mouse-clicks or menu items---whatever suits your
-program.
+The hypothetical commands @samp{show w} and @samp{show c} should show
+the appropriate parts of the General Public License. Of course, the
+commands you use may be called something other than @samp{show w} and
+@samp{show c}; they could even be mouse-clicks or menu items---whatever
+suits your program.
You should also get your employer (if you work as a programmer) or your
school, if any, to sign a ``copyright disclaimer'' for the program, if
necessary. Here is a sample; alter the names:
-@smallexample
-Yoyodyne, Inc., hereby disclaims all copyright interest in the
-program `Gnomovision' (a program to direct compilers to make passes
-at assemblers) written by James Hacker.
+@example
+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 smallexample
+@end example
+
+This General Public License does not permit incorporating your program into
+proprietary programs. If your program is a subroutine library, you may
+consider it more useful to permit linking proprietary applications with the
+library. If this is what you want to do, use the GNU Library General
+Public License instead of this License.
-That's all there is to it!
@node Index, , Copying, Top
@unnumbered Index
projects / binutils.git / blobdiff