--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,13 @@
 2010-03-07  Bruno Haible  <bruno@clisp.org>
 
+	Tests of module 'sys_socket' in C++ mode.
+	* tests/test-sys_socket-c++.cc: New file.
+	* modules/sys_socket-tests (Files): Add it and tests/signature.h.
+	(Depends-on): Add ansi-c++-opt.
+	(Makefile.am): Arrange to compile and run test-sys_socket-c++.
+	* m4/sys_socket_h.m4 (gl_SYS_SOCKET_MODULE_INDICATOR): Invoke
+	gl_MODULE_INDICATOR.
+
 	Tests of module 'sys_select' in C++ mode.
 	* tests/test-sys_select-c++.cc: New file.
 	* modules/sys_select-tests (Files): Add it and tests/signature.h.

--- a/m4/sys_socket_h.m4
+++ b/m4/sys_socket_h.m4
@@ -1,4 +1,4 @@
-# sys_socket_h.m4 serial 14
+# sys_socket_h.m4 serial 15
 dnl Copyright (C) 2005-2010 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -134,6 +134,8 @@
   dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
   AC_REQUIRE([gl_SYS_SOCKET_H_DEFAULTS])
   GNULIB_[]m4_translit([$1],[abcdefghijklmnopqrstuvwxyz./-],[ABCDEFGHIJKLMNOPQRSTUVWXYZ___])=1
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR([$1])
 ])
 
 AC_DEFUN([gl_SYS_SOCKET_H_DEFAULTS],

--- a/modules/sys_socket-tests
+++ b/modules/sys_socket-tests
@@ -1,7 +1,10 @@
 Files:
 tests/test-sys_socket.c
+tests/test-sys_socket-c++.cc
+tests/signature.h
 
 Depends-on:
+ansi-c++-opt
 
 configure.ac:
 AC_CHECK_FUNCS_ONCE([shutdown])
@@ -9,3 +12,9 @@
 Makefile.am:
 TESTS += test-sys_socket
 check_PROGRAMS += test-sys_socket
+if ANSICXX
+TESTS += test-sys_socket-c++
+check_PROGRAMS += test-sys_socket-c++
+test_sys_socket_c___SOURCES = test-sys_socket-c++.cc
+test_sys_socket_c___LDADD = $(LDADD) $(LIBINTL) $(LIBSOCKET)
+endif

new file mode 100644
--- /dev/null
+++ b/tests/test-sys_socket-c++.cc
@@ -0,0 +1,103 @@
+/* Test of <sys/socket.h> substitute in C++ mode.
+   Copyright (C) 2010 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2010.  */
+
+#define GNULIB_NAMESPACE gnulib
+#include <config.h>
+
+#include <sys/socket.h>
+
+#include "signature.h"
+
+
+#if GNULIB_SOCKET
+SIGNATURE_CHECK (GNULIB_NAMESPACE::socket, int, (int, int, int));
+#endif
+
+#if GNULIB_CONNECT
+SIGNATURE_CHECK (GNULIB_NAMESPACE::connect, int,
+                 (int, const struct sockaddr *, socklen_t));
+#endif
+
+#if GNULIB_ACCEPT
+SIGNATURE_CHECK (GNULIB_NAMESPACE::accept, int,
+                 (int, struct sockaddr *, socklen_t *));
+#endif
+
+#if GNULIB_BIND
+SIGNATURE_CHECK (GNULIB_NAMESPACE::bind, int,
+                 (int, const struct sockaddr *, socklen_t));
+#endif
+
+#if GNULIB_GETPEERNAME
+SIGNATURE_CHECK (GNULIB_NAMESPACE::getpeername, int,
+                 (int, struct sockaddr *, socklen_t *));
+#endif
+
+#if GNULIB_GETSOCKNAME
+SIGNATURE_CHECK (GNULIB_NAMESPACE::getsockname, int,
+                 (int, struct sockaddr *, socklen_t *));
+#endif
+
+#if GNULIB_GETSOCKOPT
+SIGNATURE_CHECK (GNULIB_NAMESPACE::getsockopt, int,
+                 (int, int, int, void *, socklen_t *));
+#endif
+
+#if GNULIB_LISTEN
+SIGNATURE_CHECK (GNULIB_NAMESPACE::listen, int, (int, int));
+#endif
+
+#if GNULIB_RECV
+SIGNATURE_CHECK (GNULIB_NAMESPACE::recv, ssize_t, (int, void *, size_t, int));
+#endif
+
+#if GNULIB_SEND
+SIGNATURE_CHECK (GNULIB_NAMESPACE::send, ssize_t,
+                 (int, const void *, size_t, int));
+#endif
+
+#if GNULIB_RECVFROM
+SIGNATURE_CHECK (GNULIB_NAMESPACE::recvfrom, ssize_t,
+                 (int, void *, size_t, int, struct sockaddr *, socklen_t *));
+#endif
+
+#if GNULIB_SENDTO
+SIGNATURE_CHECK (GNULIB_NAMESPACE::sendto, ssize_t,
+                 (int, const void *, size_t, int,
+                  const struct sockaddr *, socklen_t));
+#endif
+
+#if GNULIB_SETSOCKOPT
+SIGNATURE_CHECK (GNULIB_NAMESPACE::setsockopt, int,
+                 (int, int, int, const void *, socklen_t));
+#endif
+
+#if GNULIB_SHUTDOWN
+SIGNATURE_CHECK (GNULIB_NAMESPACE::shutdown, int, (int, int));
+#endif
+
+#if GNULIB_ACCEPT4
+SIGNATURE_CHECK (GNULIB_NAMESPACE::accept4, int,
+                 (int, struct sockaddr *, socklen_t *, int));
+#endif
+
+
+int
+main ()
+{
+}