view lib/freadahead.h @ 37246:5cfb3a67238d

regex: avoid glibc deadlock during configure glibc has a known bug where certain corruptions of the heap can cause malloc to default to printing a debug message that includes a backtrace, but the act of getting the backtrace uses dlopen which in turn calls into malloc, causing a recursive lock ending in deadlock. Thus, when configure is probing for a known glibc heap corruption bug, the overall configure would hang. The solution suggested by glibc developers is to force malloc to quit printing debug messages, which avoids recursive malloc. * m4/regex.m4 (gl_REGEX): Avoid recursive malloc deadlock when glibc bug 15078 in turn triggers bug 16159. Reported by Michal Privoznik. Signed-off-by: Eric Blake <eblake@redhat.com>
author Eric Blake <eblake@redhat.com>
date Tue, 03 Dec 2013 10:34:13 -0700
parents c741bc27922a
children 344018b6e5d7
line wrap: on
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/* Retrieve information about a FILE stream.
   Copyright (C) 2007-2013 Free Software Foundation, Inc.

   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 3 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
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include <stddef.h>
#include <stdio.h>

/* Assuming the stream STREAM is open for reading:
   Return the number of bytes waiting in the input buffer of STREAM.
   This includes both the bytes that have been read from the underlying input
   source and the bytes that have been pushed back through 'ungetc'.

   If this number is 0 and the stream is not currently writing,
   fflush (STREAM) is known to be a no-op.

   STREAM must not be wide-character oriented.  */

#if HAVE___FREADAHEAD /* musl libc */

# include <stdio_ext.h>
# define freadahead(stream) __freadahead (stream)

#else

# ifdef __cplusplus
extern "C" {
# endif

extern size_t freadahead (FILE *stream) _GL_ATTRIBUTE_PURE;

# ifdef __cplusplus
}
# endif

#endif