1# calloc.m4 serial 15
2
3# Copyright (C) 2004-2012 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.
7
8# Written by Jim Meyering.
9
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.
14
15# _AC_FUNC_CALLOC_IF([IF-WORKS], [IF-NOT])
16# -------------------------------------
17# If 'calloc (0, 0)' is properly handled, run IF-WORKS, otherwise, IF-NOT.
18AC_DEFUN([_AC_FUNC_CALLOC_IF],
19[
20  AC_REQUIRE([AC_TYPE_SIZE_T])dnl
21  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
22  AC_CACHE_CHECK([for GNU libc compatible calloc],
23    [ac_cv_func_calloc_0_nonnull],
24    [AC_RUN_IFELSE(
25       [AC_LANG_PROGRAM(
26          [AC_INCLUDES_DEFAULT],
27          [[int result = 0;
28            if (!calloc (0, 0))
29              result |= 1;
30            if (calloc ((size_t) -1 / 8 + 1, 8))
31              result |= 2;
32            return result;
33          ]])],
34       [ac_cv_func_calloc_0_nonnull=yes],
35       [ac_cv_func_calloc_0_nonnull=no],
36       [case "$host_os" in
37                  # Guess yes on glibc systems.
38          *-gnu*) ac_cv_func_calloc_0_nonnull="guessing yes" ;;
39                  # If we don't know, assume the worst.
40          *)      ac_cv_func_calloc_0_nonnull="guessing no" ;;
41        esac
42       ])])
43  case "$ac_cv_func_calloc_0_nonnull" in
44    *yes)
45      $1
46      ;;
47    *)
48      $2
49      ;;
50  esac
51])# AC_FUNC_CALLOC
52
53
54# gl_FUNC_CALLOC_GNU
55# ------------------
56# Report whether 'calloc (0, 0)' is properly handled, and replace calloc if
57# needed.
58AC_DEFUN([gl_FUNC_CALLOC_GNU],
59[
60  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
61  _AC_FUNC_CALLOC_IF(
62    [AC_DEFINE([HAVE_CALLOC_GNU], [1],
63               [Define to 1 if your system has a GNU libc compatible 'calloc'
64                function, and to 0 otherwise.])],
65    [AC_DEFINE([HAVE_CALLOC_GNU], [0])
66     REPLACE_CALLOC=1
67    ])
68])# gl_FUNC_CALLOC_GNU
69
70
71# gl_FUNC_CALLOC_POSIX
72# --------------------
73# Test whether 'calloc' is POSIX compliant (sets errno to ENOMEM when it
74# fails), and replace calloc if it is not.
75AC_DEFUN([gl_FUNC_CALLOC_POSIX],
76[
77  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
78  AC_REQUIRE([gl_CHECK_MALLOC_POSIX])
79  if test $gl_cv_func_malloc_posix = yes; then
80    AC_DEFINE([HAVE_CALLOC_POSIX], [1],
81      [Define if the 'calloc' function is POSIX compliant.])
82  else
83    REPLACE_CALLOC=1
84  fi
85])
86