1 # Check whether free (NULL) is supposed to work.
3 # Copyright (C) 2003, 2004 Free Software Foundation, Inc.
4 # This file is free software; the Free Software Foundation
5 # gives unlimited permission to copy and/or distribute it,
6 # with or without modifications, as long as this notice is preserved.
8 # Written by Paul Eggert.
10 # We can't test for free (NULL) even at runtime, since it might
11 # happen to "work" for our test program, but not in general. So, be
12 # conservative and use feature tests for relatively modern hosts,
13 # where free (NULL) is known to work. This costs a bit of
14 # performance on some older hosts, but we can fix that later if
17 AC_DEFUN([gl_FUNC_FREE],
19 AC_CHECK_HEADERS_ONCE(unistd.h)
20 AC_CACHE_CHECK([whether free (NULL) is known to work],
24 [[@%:@if HAVE_UNISTD_H
25 @%:@include <unistd.h>
27 [[@%:@if _POSIX_VERSION < 199009L && \
28 (defined unix || defined _unix || defined _unix_ \
29 || defined __unix || defined __unix__)
30 @%:@error "'free (NULL)' is not known to work"
32 [gl_cv_func_free=yes],
33 [gl_cv_func_free=no])])
35 if test $gl_cv_func_free = no; then
37 AC_DEFINE(free, rpl_free,
38 [Define to rpl_free if the replacement function should be used.])
42 # Prerequisites of lib/free.c.
43 AC_DEFUN([gl_PREREQ_FREE], [:])