X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;ds=sidebyside;f=m4%2Fstpncpy.m4;h=d2344acc4a51ee06862732f893070c26778fd27d;hb=820ad111e4c5b7877f18f29246059c86ee70351d;hp=768cced0270728269eb04510cdd5eca973a1eb8c;hpb=1080617a7d04cdf1a1d3b1e390859af371d485d7;p=gnulib.git

diff --git a/m4/stpncpy.m4 b/m4/stpncpy.m4
index 768cced02..d2344acc4 100644
--- a/m4/stpncpy.m4
+++ b/m4/stpncpy.m4
@@ -1,19 +1,37 @@
-# 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 11
+dnl Copyright (C) 2002-2003, 2005-2007, 2009-2010 Free Software Foundation,
+dnl 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])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
-  AC_CACHE_CHECK([for working stpncpy], gl_cv_func_stpncpy, [
-    AC_TRY_RUN([
+  dnl The stpncpy() declaration in lib/string.in.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_CHECK_FUNCS_ONCE([stpncpy])
+  if test $ac_cv_func_stpncpy = yes; then
+    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";
@@ -29,21 +47,26 @@ int main () {
   if (stpncpy (dest, src, 7) != dest + 5) exit(1);
   exit(0);
 }
-], gl_cv_func_stpncpy=yes, gl_cv_func_stpncpy=no,
-  [AC_EGREP_CPP([Thanks for using GNU], [
+], [gl_cv_func_stpncpy=yes], [gl_cv_func_stpncpy=no],
+        [AC_EGREP_CPP([Thanks for using GNU], [
 #include <features.h>
 #ifdef __GNU_LIBRARY__
   Thanks for using GNU
 #endif
-], gl_cv_func_stpncpy=yes, gl_cv_func_stpncpy=no)])])
-
-  if test $gl_cv_func_stpncpy = yes; then
-    AC_DEFINE(HAVE_STPNCPY, 1,
-      [Define if you have the stpncpy() function and it works.])
+], [gl_cv_func_stpncpy=yes], [gl_cv_func_stpncpy=no])
+        ])
+    ])
+    if test $gl_cv_func_stpncpy = yes; then
+      AC_DEFINE([HAVE_STPNCPY], [1],
+        [Define if you have the stpncpy() function and it works.])
+    else
+      REPLACE_STPNCPY=1
+      AC_LIBOBJ([stpncpy])
+      gl_PREREQ_STPNCPY
+    fi
   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 +75,3 @@ int main () {
 AC_DEFUN([gl_PREREQ_STPNCPY], [
   :
 ])
-