pread: Update documentation.

[gnulib.git] / m4 / calloc.m4

diff --git a/m4/calloc.m4 b/m4/calloc.m4
index fee15dd..22cffbd 100644 (file)
--- a/m4/calloc.m4
+++ b/m4/calloc.m4
@@ -1,32 +1,28 @@
-#serial 1
+# calloc.m4 serial 9
 
-# FIXME: remove this whole file once we can depend
-# on having the definition from autoconf.
-undefine([AC_FUNC_CALLOC])
+# Copyright (C) 2004-2010 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
 
-# Determine whether calloc (N, S) returns non-NULL when N*S is zero.
+# Written by Jim Meyering.
+
+# Determine whether calloc (N, S) returns non-NULL when N*S is zero,
+# and returns NULL when N*S overflows.
 # If so, define HAVE_CALLOC.  Otherwise, define calloc to rpl_calloc
 # and arrange to use a calloc wrapper function that does work in that case.
 
-# _AC_FUNC_CALLOC_IF(IF-WORKS, IF-NOT)
+# _AC_FUNC_CALLOC_IF([IF-WORKS], [IF-NOT])
 # -------------------------------------
 # If `calloc (0, 0)' is properly handled, run IF-WORKS, otherwise, IF-NOT.
 AC_DEFUN([_AC_FUNC_CALLOC_IF],
-[AC_REQUIRE([AC_HEADER_STDC])dnl
-AC_CHECK_HEADERS(stdlib.h)
-AC_CACHE_CHECK([for GNU libc compatible calloc], ac_cv_func_calloc_0_nonnull,
-[AC_RUN_IFELSE(
-[AC_LANG_PROGRAM(
-[[#if STDC_HEADERS || HAVE_STDLIB_H
-# include <stdlib.h>
-#else
-char *calloc ();
-#endif
-]],
-                [exit (calloc (0, 0) ? 0 : 1);])],
-              [ac_cv_func_calloc_0_nonnull=yes],
-              [ac_cv_func_calloc_0_nonnull=no],
-              [ac_cv_func_calloc_0_nonnull=no])])
+[AC_REQUIRE([AC_TYPE_SIZE_T])dnl
+AC_CACHE_CHECK([for GNU libc compatible calloc], [ac_cv_func_calloc_0_nonnull],
+[AC_RUN_IFELSE([AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT],
+                  [[exit (!calloc (0, 0) || calloc ((size_t) -1 / 8 + 1, 8));]])],
+               [ac_cv_func_calloc_0_nonnull=yes],
+               [ac_cv_func_calloc_0_nonnull=no],
+               [ac_cv_func_calloc_0_nonnull=no])])
 AS_IF([test $ac_cv_func_calloc_0_nonnull = yes], [$1], [$2])
 ])# AC_FUNC_CALLOC
 
@@ -37,11 +33,30 @@ AS_IF([test $ac_cv_func_calloc_0_nonnull = yes], [$1], [$2])
 # needed.
 AC_DEFUN([AC_FUNC_CALLOC],
 [_AC_FUNC_CALLOC_IF(
-  [AC_DEFINE([HAVE_CALLOC], 1,
-            [Define to 1 if your system has a GNU libc compatible `calloc'
-             function, and to 0 otherwise.])],
-  [AC_DEFINE([HAVE_CALLOC], 0)
+  [AC_DEFINE([HAVE_CALLOC], [1],
+             [Define to 1 if your system has a GNU libc compatible `calloc'
+              function, and to 0 otherwise.])],
+  [AC_DEFINE([HAVE_CALLOC], [0])
    AC_LIBOBJ([calloc])
    AC_DEFINE([calloc], [rpl_calloc],
       [Define to rpl_calloc if the replacement function should be used.])])
 ])# AC_FUNC_CALLOC
+
+
+# gl_FUNC_CALLOC_POSIX
+# --------------------
+# Test whether 'calloc' is POSIX compliant (sets errno to ENOMEM when it
+# fails), and replace calloc if it is not.
+AC_DEFUN([gl_FUNC_CALLOC_POSIX],
+[
+  AC_REQUIRE([gl_CHECK_MALLOC_POSIX])
+  if test $gl_cv_func_malloc_posix = yes; then
+    HAVE_CALLOC_POSIX=1
+    AC_DEFINE([HAVE_CALLOC_POSIX], [1],
+      [Define if the 'calloc' function is POSIX compliant.])
+  else
+    AC_LIBOBJ([calloc])
+    HAVE_CALLOC_POSIX=0
+  fi
+  AC_SUBST([HAVE_CALLOC_POSIX])
+])