1 /* Make free() preserve errno.
2 
3    Copyright (C) 2003, 2006, 2009-2021 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
rpl_free(void * p)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
54