3 # Copyright (C) 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 Jim Meyering.
10 # Determine whether calloc (N, S) returns non-NULL when N*S is zero,
11 # and returns NULL when N*S overflows.
12 # If so, define HAVE_CALLOC. Otherwise, define calloc to rpl_calloc
13 # and arrange to use a calloc wrapper function that does work in that case.
15 # _AC_FUNC_CALLOC_IF(IF-WORKS, IF-NOT)
16 # -------------------------------------
17 # If `calloc (0, 0)' is properly handled, run IF-WORKS, otherwise, IF-NOT.
18 AC_DEFUN([_AC_FUNC_CALLOC_IF],
19 [AC_REQUIRE([AC_HEADER_STDC])dnl
20 AC_REQUIRE([AC_TYPE_SIZE_T])dnl
21 AC_CHECK_HEADERS(stdlib.h)
22 AC_CACHE_CHECK([for GNU libc compatible calloc], ac_cv_func_calloc_0_nonnull,
23 [AC_RUN_IFELSE([AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT],
24 [exit (!calloc (0, 0) || calloc ((size_t) -1 / 8 + 1, 8));])],
25 [ac_cv_func_calloc_0_nonnull=yes],
26 [ac_cv_func_calloc_0_nonnull=no],
27 [ac_cv_func_calloc_0_nonnull=no])])
28 AS_IF([test $ac_cv_func_calloc_0_nonnull = yes], [$1], [$2])
34 # Report whether `calloc (0, 0)' is properly handled, and replace calloc if
36 AC_DEFUN([AC_FUNC_CALLOC],
38 [AC_DEFINE([HAVE_CALLOC], 1,
39 [Define to 1 if your system has a GNU libc compatible `calloc'
40 function, and to 0 otherwise.])],
41 [AC_DEFINE([HAVE_CALLOC], 0)
43 AC_DEFINE([calloc], [rpl_calloc],
44 [Define to rpl_calloc if the replacement function should be used.])])