--- a/ChangeLog	Thu Apr 08 03:02:12 2010 +0100
+++ b/ChangeLog	Sat Apr 10 11:29:14 2010 +0200
@@ -1,3 +1,14 @@
+2010-04-10  Bruno Haible  <bruno@clisp.org>
+
+	strnlen: Fix warning in C++ mode on MacOS X.
+	* lib/string.in.h (strnlen): Use the modern idiom.
+	* m4/strnlen.m4 (gl_FUNC_STRNLEN): Set REPLACE_STRNLEN to 1, instead of
+	defining strnlen as a macro already in <config.h>.
+	* m4/string_h.m4 (gl_HEADER_STRING_H_DEFAULTS): Initialize
+	REPLACE_STRNLEN.
+	* modules/string (Makefile.am): Substitute REPLACE_STRNLEN.
+	Reported by Jarno Rajahalme <jarno.rajahalme@nsn.com>.
+
 2010-04-08  James Youngman  <jay@gnu.org>
 
 	* doc/manywarnings.texi (manywarnings): Add missing parenthesis in

--- a/lib/string.in.h	Thu Apr 08 03:02:12 2010 +0100
+++ b/lib/string.in.h	Sat Apr 10 11:29:14 2010 +0200
@@ -372,12 +372,23 @@
    MAXLEN bytes.  If no '\0' terminator is found in that many bytes,
    return MAXLEN.  */
 #if @GNULIB_STRNLEN@
-# if ! @HAVE_DECL_STRNLEN@
+# if @REPLACE_STRNLEN@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef strnlen
+#   define strnlen rpl_strnlen
+#  endif
+_GL_FUNCDECL_RPL (strnlen, size_t, (char const *__string, size_t __maxlen)
+                                   __attribute__ ((__pure__))
+                                   _GL_ARG_NONNULL ((1)));
+_GL_CXXALIAS_RPL (strnlen, size_t, (char const *__string, size_t __maxlen));
+# else
+#  if ! @HAVE_DECL_STRNLEN@
 _GL_FUNCDECL_SYS (strnlen, size_t, (char const *__string, size_t __maxlen)
                                    __attribute__ ((__pure__))
                                    _GL_ARG_NONNULL ((1)));
+#  endif
+_GL_CXXALIAS_SYS (strnlen, size_t, (char const *__string, size_t __maxlen));
 # endif
-_GL_CXXALIAS_SYS (strnlen, size_t, (char const *__string, size_t __maxlen));
 _GL_CXXALIASWARN (strnlen);
 #elif defined GNULIB_POSIXCHECK
 # undef strnlen

--- a/m4/string_h.m4	Thu Apr 08 03:02:12 2010 +0100
+++ b/m4/string_h.m4	Sat Apr 10 11:29:14 2010 +0200
@@ -5,7 +5,7 @@
 # gives unlimited permission to copy and/or distribute it,
 # with or without modifications, as long as this notice is preserved.
 
-# serial 16
+# serial 17
 
 # Written by Paul Eggert.
 
@@ -105,6 +105,7 @@
   REPLACE_STRERROR=0;           AC_SUBST([REPLACE_STRERROR])
   REPLACE_STRNCAT=0;            AC_SUBST([REPLACE_STRNCAT])
   REPLACE_STRNDUP=0;            AC_SUBST([REPLACE_STRNDUP])
+  REPLACE_STRNLEN=0;            AC_SUBST([REPLACE_STRNLEN])
   REPLACE_STRSIGNAL=0;          AC_SUBST([REPLACE_STRSIGNAL])
   REPLACE_STRTOK_R=0;           AC_SUBST([REPLACE_STRTOK_R])
   UNDEFINE_STRTOK_R=0;          AC_SUBST([UNDEFINE_STRTOK_R])

--- a/m4/strnlen.m4	Thu Apr 08 03:02:12 2010 +0100
+++ b/m4/strnlen.m4	Sat Apr 10 11:29:14 2010 +0200
@@ -1,4 +1,4 @@
-# strnlen.m4 serial 10
+# strnlen.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
@@ -7,10 +7,11 @@
 
 AC_DEFUN([gl_FUNC_STRNLEN],
 [
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+
   dnl Persuade glibc <string.h> to declare strnlen().
   AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
-  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
   AC_CHECK_DECLS_ONCE([strnlen])
   if test $ac_cv_have_decl_strnlen = no; then
     HAVE_DECL_STRNLEN=0
@@ -18,12 +19,11 @@
 
   AC_FUNC_STRNLEN
   if test $ac_cv_func_strnlen_working = no; then
+    REPLACE_STRNLEN=1
     # This is necessary because automake-1.6.1 doesn't understand
     # that the above use of AC_FUNC_STRNLEN means we may have to use
     # lib/strnlen.c.
     #AC_LIBOBJ([strnlen])
-    AC_DEFINE([strnlen], [rpl_strnlen],
-      [Define to rpl_strnlen if the replacement function should be used.])
     gl_PREREQ_STRNLEN
   fi
 ])

--- a/modules/string	Thu Apr 08 03:02:12 2010 +0100
+++ b/modules/string	Sat Apr 10 11:29:14 2010 +0200
@@ -89,6 +89,7 @@
 	      -e 's|@''REPLACE_STRERROR''@|$(REPLACE_STRERROR)|g' \
 	      -e 's|@''REPLACE_STRNCAT''@|$(REPLACE_STRNCAT)|g' \
 	      -e 's|@''REPLACE_STRNDUP''@|$(REPLACE_STRNDUP)|g' \
+	      -e 's|@''REPLACE_STRNLEN''@|$(REPLACE_STRNLEN)|g' \
 	      -e 's|@''REPLACE_STRSIGNAL''@|$(REPLACE_STRSIGNAL)|g' \
 	      -e 's|@''REPLACE_STRTOK_R''@|$(REPLACE_STRTOK_R)|g' \
 	      -e 's|@''UNDEFINE_STRTOK_R''@|$(UNDEFINE_STRTOK_R)|g' \