Merge commit 'a39d4083cab589d7cd6a13e8a4b8db8875261d75'

[gnulib.git] / m4 / strndup.m4

diff --git a/m4/strndup.m4 b/m4/strndup.m4
index 5794504..55df039 100644 (file)
--- a/m4/strndup.m4
+++ b/m4/strndup.m4
@@ -1,23 +1,55 @@
-# strndup.m4 serial 4
-dnl Copyright (C) 2002, 2003, 2005 Free Software Foundation, Inc.
+# strndup.m4 serial 21
+dnl Copyright (C) 2002-2003, 2005-2014 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_STRNDUP],
 [
-  AC_LIBSOURCES([strndup.c, strndup.h])
-
   dnl Persuade glibc <string.h> to declare strndup().
-  AC_REQUIRE([AC_GNU_SOURCE])
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
-  AC_REPLACE_FUNCS(strndup)
-  if test $ac_cv_func_strndup = no; then
-    gl_PREREQ_STRNDUP
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  AC_CHECK_DECLS_ONCE([strndup])
+  AC_CHECK_FUNCS_ONCE([strndup])
+  if test $ac_cv_have_decl_strndup = no; then
+    HAVE_DECL_STRNDUP=0
   fi
-])
 
-# Prerequisites of lib/strndup.c.
-AC_DEFUN([gl_PREREQ_STRNDUP], [
-  AC_CHECK_DECLS(strnlen)
+  if test $ac_cv_func_strndup = yes; then
+    HAVE_STRNDUP=1
+    # AIX 4.3.3, AIX 5.1 have a function that fails to add the terminating '\0'.
+    AC_CACHE_CHECK([for working strndup], [gl_cv_func_strndup_works],
+      [AC_RUN_IFELSE([
+         AC_LANG_PROGRAM([[#include <string.h>
+                           #include <stdlib.h>]], [[
+#if !HAVE_DECL_STRNDUP
+  extern
+  #ifdef __cplusplus
+  "C"
+  #endif
+  char *strndup (const char *, size_t);
+#endif
+  char *s;
+  s = strndup ("some longer string", 15);
+  free (s);
+  s = strndup ("shorter string", 13);
+  return s[13] != '\0';]])],
+         [gl_cv_func_strndup_works=yes],
+         [gl_cv_func_strndup_works=no],
+         [
+changequote(,)dnl
+          case $host_os in
+            aix | aix[3-6]*) gl_cv_func_strndup_works="guessing no";;
+            *)               gl_cv_func_strndup_works="guessing yes";;
+          esac
+changequote([,])dnl
+         ])])
+    case $gl_cv_func_strndup_works in
+      *no) REPLACE_STRNDUP=1 ;;
+    esac
+  else
+    HAVE_STRNDUP=0
+  fi
 ])