autoupdate

[gnulib.git] / m4 / stpncpy.m4

diff --git a/m4/stpncpy.m4 b/m4/stpncpy.m4
index 768cced..aad0375 100644 (file)
--- a/m4/stpncpy.m4
+++ b/m4/stpncpy.m4
@@ -1,19 +1,34 @@
-# stpncpy.m4 serial 1
-dnl Copyright (C) 2002-2003 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.
+# stpncpy.m4 serial 7
+dnl Copyright (C) 2002-2003, 2005-2007 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.
 
 AC_DEFUN([gl_FUNC_STPNCPY],
 [
   dnl Persuade glibc <string.h> to declare stpncpy().
   AC_REQUIRE([AC_GNU_SOURCE])
 
+  dnl The stpncpy() declaration in lib/string_.h uses 'restrict'.
+  AC_REQUIRE([AC_C_RESTRICT])
+
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+
+  dnl Both glibc and AIX (4.3.3, 5.1) have an stpncpy() function
+  dnl declared in <string.h>. Its side effects are the same as those
+  dnl of strncpy():
+  dnl      stpncpy (dest, src, n)
+  dnl overwrites dest[0..n-1], min(strlen(src),n) bytes coming from src,
+  dnl and the remaining bytes being NULs.  However, the return value is
+  dnl   in glibc:   dest + min(strlen(src),n)
+  dnl   in AIX:     dest + max(0,n-1)
+  dnl Only the glibc return value is useful in practice.
+
   AC_CACHE_CHECK([for working stpncpy], gl_cv_func_stpncpy, [
     AC_TRY_RUN([
 #include <stdlib.h>
+#include <string.h> /* for strcpy */
+/* The stpncpy prototype is missing in <string.h> on AIX 4.  */
 extern char *stpncpy (char *dest, const char *src, size_t n);
 int main () {
   const char *src = "Hello";
@@ -41,9 +56,8 @@ int main () {
     AC_DEFINE(HAVE_STPNCPY, 1,
       [Define if you have the stpncpy() function and it works.])
   else
+    HAVE_STPNCPY=0
     AC_LIBOBJ([stpncpy])
-    AC_DEFINE(stpncpy, rpl_stpncpy,
-      [Define to rpl_stpncpy if the replacement function should be used.])
     gl_PREREQ_STPNCPY
   fi
 ])
@@ -52,4 +66,3 @@ int main () {
 AC_DEFUN([gl_PREREQ_STPNCPY], [
   :
 ])
-