1 /* Make free() preserve errno.
2
3 Copyright (C) 2003, 2006, 2009-2023 Free Software Foundation, Inc.
4
5 This file is free software: you can redistribute it and/or modify
6 it under the terms of the GNU Lesser General Public License as
7 published by the Free Software Foundation; either version 2.1 of the
8 License, or (at your option) any later version.
9
10 This file is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public License
16 along with this program. If not, see <https://www.gnu.org/licenses/>. */
17
18 /* written by Paul Eggert */
19
20 #include <config.h>
21
22 /* Specification. */
23 #include <stdlib.h>
24
25 /* A function definition is only needed if HAVE_FREE_POSIX is not defined. */
26 #if !HAVE_FREE_POSIX
27
28 # include <errno.h>
29
30 void
31 rpl_free (void *p)
32 # undef free
33 {
34 # if defined __GNUC__ && !defined __clang__
35 /* An invalid GCC optimization
36 <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98396>
37 would optimize away the assignments in the code below, when link-time
38 optimization (LTO) is enabled. Make the code more complicated, so that
39 GCC does not grok how to optimize it. */
40 int err[2];
41 err[0] = errno;
42 err[1] = errno;
43 errno = 0;
44 free (p);
45 errno = err[errno == 0];
46 # else
47 int err = errno;
48 free (p);
49 errno = err;
50 # endif
51 }
52
53 #endif