ansi-c++-opt: Provide option --enable-c++/--disable-c++ when possible.

[gnulib.git] / m4 / malloc.m4

diff --git a/m4/malloc.m4 b/m4/malloc.m4
index b491ad4..fe5befc 100644 (file)
--- a/m4/malloc.m4
+++ b/m4/malloc.m4
@@ -1,34 +1,62 @@
-#serial 3
+# malloc.m4 serial 10
+dnl Copyright (C) 2007, 2009, 2010 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.
-dnl
-
-AC_DEFUN(jm_FUNC_MALLOC,
+# gl_FUNC_MALLOC_GNU
+# ------------------
+# Test whether 'malloc (0)' is handled like in GNU libc, and replace malloc if
+# it is not.
+AC_DEFUN([gl_FUNC_MALLOC_GNU],
 [
- dnl xmalloc.c requires that this symbol be defined so it doesn't
- dnl mistakenly use a broken malloc -- as it might if this test were omitted.
- AC_DEFINE_UNQUOTED(HAVE_DONE_WORKING_MALLOC_CHECK, 1,
-                    [Define if the malloc check has been performed. ])
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  dnl _AC_FUNC_MALLOC_IF is defined in Autoconf.
+  _AC_FUNC_MALLOC_IF(
+    [AC_DEFINE([HAVE_MALLOC], [1],
+               [Define to 1 if your system has a GNU libc compatible 'malloc'
+                function, and to 0 otherwise.])],
+    [AC_DEFINE([HAVE_MALLOC], [0])
+     gl_REPLACE_MALLOC
+    ])
+])
 
- AC_CACHE_CHECK([for working malloc], jm_cv_func_working_malloc,
-  [AC_TRY_RUN([
-    char *malloc ();
-    int
-    main ()
-    {
-      exit (malloc (0) ? 0 : 1);
-    }
-         ],
-        jm_cv_func_working_malloc=yes,
-        jm_cv_func_working_malloc=no,
-        dnl When crosscompiling, assume malloc is broken.
-        jm_cv_func_working_malloc=no)
-  ])
-  if test $jm_cv_func_working_malloc = no; then
-    LIBOBJS="$LIBOBJS malloc.$ac_objext"
-    AC_DEFINE_UNQUOTED(malloc, rpl_malloc,
-      [Define to rpl_malloc if the replacement function should be used.])
+# 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([gl_STDLIB_H_DEFAULTS])
+  AC_REQUIRE([gl_CHECK_MALLOC_POSIX])
+  if test $gl_cv_func_malloc_posix = yes; then
+    AC_DEFINE([HAVE_MALLOC_POSIX], [1],
+      [Define if the 'malloc' function is POSIX compliant.])
+  else
+    gl_REPLACE_MALLOC
   fi
 ])
+
+# 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])
+    ])
+])
+
+AC_DEFUN([gl_REPLACE_MALLOC],
+[
+  AC_LIBOBJ([malloc])
+  REPLACE_MALLOC=1
+])