New module 'errno'.

[gnulib.git] / m4 / malloc.m4

diff --git a/m4/malloc.m4 b/m4/malloc.m4
index 2452acf..764f2a9 100644 (file)
--- a/m4/malloc.m4
+++ b/m4/malloc.m4
@@ -1,25 +1,41 @@
-# malloc.m4 serial 7
-dnl Copyright (C) 2002 Free Software Foundation, Inc.
-dnl This file is free software, distributed under the terms of the GNU
-dnl General Public License.  As a special exception to the GNU General
-dnl Public License, this file may be distributed as part of a program
-dnl that contains a configuration script generated by Autoconf, under
-dnl the same distribution terms as the rest of that program.
+# malloc.m4 serial 8
+dnl Copyright (C) 2007 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
 
-dnl From Jim Meyering.
-dnl Determine whether malloc accepts 0 as its argument.
-dnl If it doesn't, arrange to use the replacement function.
-
-AC_DEFUN([jm_FUNC_MALLOC],
+# gl_FUNC_MALLOC_POSIX
+# --------------------
+# Test whether 'malloc' is POSIX compliant (sets errno to ENOMEM when it
+# fails), and replace malloc if it is not.
+AC_DEFUN([gl_FUNC_MALLOC_POSIX],
 [
-  AC_REQUIRE([AC_FUNC_MALLOC])
-  dnl autoconf < 2.57 used the symbol ac_cv_func_malloc_works.
-  if test X"$ac_cv_func_malloc_0_nonnull" = Xno || test X"$ac_cv_func_malloc_works" = Xno; then
-    gl_PREREQ_MALLOC
+  AC_REQUIRE([gl_CHECK_MALLOC_POSIX])
+  if test $gl_cv_func_malloc_posix = yes; then
+    HAVE_MALLOC_POSIX=1
+    AC_DEFINE([HAVE_MALLOC_POSIX], 1,
+      [Define if the 'malloc' function is POSIX compliant.])
+  else
+    AC_LIBOBJ([malloc])
+    HAVE_MALLOC_POSIX=0
   fi
+  AC_SUBST([HAVE_MALLOC_POSIX])
 ])
 
-# Prerequisites of lib/malloc.c.
-AC_DEFUN([gl_PREREQ_MALLOC], [
-  :
+# Test whether malloc, realloc, calloc are POSIX compliant,
+# Set gl_cv_func_malloc_posix to yes or no accordingly.
+AC_DEFUN([gl_CHECK_MALLOC_POSIX],
+[
+  AC_CACHE_CHECK([whether malloc, realloc, calloc are POSIX compliant],
+    [gl_cv_func_malloc_posix],
+    [
+      dnl It is too dangerous to try to allocate a large amount of memory:
+      dnl some systems go to their knees when you do that. So assume that
+      dnl all Unix implementations of the function are POSIX compliant.
+      AC_TRY_COMPILE([],
+        [#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+         choke me
+         #endif
+        ], [gl_cv_func_malloc_posix=yes], [gl_cv_func_malloc_posix=no])
+    ])
 ])