+ /* 0 = none, >0 = reader (index of writer),
+ <0 = writer (negative index of reader).
+ If abs (ispipe[N]) == N, then N is an end of a pipe whose other
+ end is closed. */
+ short ispipe[MAX_CALLBACK_FDS];
+
+ /* A writer stores the buffer at its index. Consecutive writes
+ realloc the buffer and add to the size. The reader indicates the
+ read part in its .size, until it has consumed it all, at which
+ point it deallocates the buffer and zeroes out both sizes. */
+ struct pipe_write_buffer
+ {
+ int size;
+ char *buffer;
+ } pipe_buffer[MAX_CALLBACK_FDS];
+