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emacs/lib/free.c
2023-01-01 05:31:12 -05:00

54 lines
1.5 KiB
C

/* Make free() preserve errno.
Copyright (C) 2003, 2006, 2009-2023 Free Software Foundation, Inc.
This file is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
This file 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
/* written by Paul Eggert */
#include <config.h>
/* Specification. */
#include <stdlib.h>
/* A function definition is only needed if HAVE_FREE_POSIX is not defined. */
#if !HAVE_FREE_POSIX
# include <errno.h>
void
rpl_free (void *p)
# undef free
{
# if defined __GNUC__ && !defined __clang__
/* An invalid GCC optimization
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98396>
would optimize away the assignments in the code below, when link-time
optimization (LTO) is enabled. Make the code more complicated, so that
GCC does not grok how to optimize it. */
int err[2];
err[0] = errno;
err[1] = errno;
errno = 0;
free (p);
errno = err[errno == 0];
# else
int err = errno;
free (p);
errno = err;
# endif
}
#endif