X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fmemcmp.m4;h=dcc22120f7999e6242c967fef0c0d0a803a10dc5;hb=0f5629a2fc2a536cfedd8d29e66c36995d8d3211;hp=a6b6d54e9b58629ebce87da635eb54afad3480cf;hpb=540fc8b65ac585024a4845136780f5808b09913d;p=gnulib.git

diff --git a/m4/memcmp.m4 b/m4/memcmp.m4
index a6b6d54e9..dcc22120f 100644
--- a/m4/memcmp.m4
+++ b/m4/memcmp.m4
@@ -1,9 +1,61 @@
-#serial 6
+# memcmp.m4 serial 16
+dnl Copyright (C) 2002-2004, 2007-2011 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.
 
-AC_DEFUN(jm_FUNC_MEMCMP,
-[AC_REQUIRE([AC_FUNC_MEMCMP])dnl
- if test $ac_cv_func_memcmp_working = no; then
-   AC_DEFINE_UNQUOTED(memcmp, rpl_memcmp,
-     [Define to rpl_memcmp if the replacement function should be used.])
- fi
+AC_DEFUN([gl_FUNC_MEMCMP],
+[
+  dnl We don't use AC_FUNC_MEMCMP any more, because it is no longer maintained
+  dnl in Autoconf and because it invokes AC_LIBOBJ.
+  AC_CACHE_CHECK([for working memcmp], [gl_cv_func_memcmp_working],
+    [AC_RUN_IFELSE(
+       [AC_LANG_PROGRAM(
+          [AC_INCLUDES_DEFAULT],
+          [[/* Some versions of memcmp are not 8-bit clean.  */
+            char c0 = '\100', c1 = '\200', c2 = '\201';
+            if (memcmp(&c0, &c2, 1) >= 0 || memcmp(&c1, &c2, 1) >= 0)
+              return 1;
+            /* The Next x86 OpenStep bug shows up only when comparing 16 bytes
+               or more and with at least one buffer not starting on a 4-byte
+               boundary.  William Lewis provided this test program.   */
+            {
+              char foo[21];
+              char bar[21];
+              int i;
+              for (i = 0; i < 4; i++)
+                {
+                  char *a = foo + i;
+                  char *b = bar + i;
+                  strcpy (a, "--------01111111");
+                  strcpy (b, "--------10000000");
+                  if (memcmp (a, b, 16) >= 0)
+                    return 1;
+                }
+              return 0;
+            }
+          ]])],
+       [gl_cv_func_memcmp_working=yes],
+       [gl_cv_func_memcmp_working=no],
+       [dnl When cross-compiling, guess memcmp works when it exists.
+        dnl This is useful for mingw.
+        AC_LINK_IFELSE(
+          [AC_LANG_PROGRAM(
+             [[#include <string.h>]],
+             [[int ret = memcmp ("foo", "bar", 0);]])],
+          [gl_cv_func_memcmp_working="guessing yes"],
+          [gl_cv_func_memcmp_working="guessing no"])
+       ])
+    ])
+  case "$gl_cv_func_memcmp_working" in
+    *yes) gl_func_memcmp=yes ;;
+    *)    gl_func_memcmp=no ;;
+  esac
+  if test $gl_func_memcmp = no; then
+    AC_DEFINE([memcmp], [rpl_memcmp],
+      [Define to rpl_memcmp if the replacement function should be used.])
+  fi
 ])
+
+# Prerequisites of lib/memcmp.c.
+AC_DEFUN([gl_PREREQ_MEMCMP], [:])