--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2010-03-28  Bruno Haible  <bruno@clisp.org>
+
+	unistd: Avoid #define replacements in C++ mode.
+	* lib/unistd.in.h (socket, connect, accept, bind, getpeername,
+	getsockname, getsockopt, listen, recv, send, recvfrom, sendto,
+	setsockopt, shutdown, select): In C++, attach a warning to the function
+	if possible, rather than #defining the symbol to a dysfunctional alias.
+	Reported by John W. Eaton <jwe@gnu.org>.
+
 2010-03-28  Bruno Haible  <bruno@clisp.org>
 
 	Fix link errors on mingw.

--- a/lib/unistd.in.h
+++ b/lib/unistd.in.h
@@ -97,46 +97,6 @@
 # include <getopt.h>
 #endif
 
-#if @GNULIB_GETHOSTNAME@
-/* Get all possible declarations of gethostname().  */
-# if @UNISTD_H_HAVE_WINSOCK2_H@
-#  if !defined _GL_SYS_SOCKET_H
-#   undef socket
-#   define socket               socket_used_without_including_sys_socket_h
-#   undef connect
-#   define connect              connect_used_without_including_sys_socket_h
-#   undef accept
-#   define accept               accept_used_without_including_sys_socket_h
-#   undef bind
-#   define bind                 bind_used_without_including_sys_socket_h
-#   undef getpeername
-#   define getpeername          getpeername_used_without_including_sys_socket_h
-#   undef getsockname
-#   define getsockname          getsockname_used_without_including_sys_socket_h
-#   undef getsockopt
-#   define getsockopt           getsockopt_used_without_including_sys_socket_h
-#   undef listen
-#   define listen               listen_used_without_including_sys_socket_h
-#   undef recv
-#   define recv                 recv_used_without_including_sys_socket_h
-#   undef send
-#   define send                 send_used_without_including_sys_socket_h
-#   undef recvfrom
-#   define recvfrom             recvfrom_used_without_including_sys_socket_h
-#   undef sendto
-#   define sendto               sendto_used_without_including_sys_socket_h
-#   undef setsockopt
-#   define setsockopt           setsockopt_used_without_including_sys_socket_h
-#   undef shutdown
-#   define shutdown             shutdown_used_without_including_sys_socket_h
-#  endif
-#  if !defined _GL_SYS_SELECT_H
-#   undef select
-#   define select               select_used_without_including_sys_select_h
-#  endif
-# endif
-#endif
-
 /* The definitions of _GL_FUNCDECL_RPL etc. are copied here.  */
 
 /* The definition of _GL_ARG_NONNULL is copied here.  */
@@ -144,6 +104,83 @@
 /* The definition of _GL_WARN_ON_USE is copied here.  */
 
 
+#if @GNULIB_GETHOSTNAME@
+/* Get all possible declarations of gethostname().  */
+# if @UNISTD_H_HAVE_WINSOCK2_H@
+#  if !defined _GL_SYS_SOCKET_H
+#   if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#    undef socket
+#    define socket              socket_used_without_including_sys_socket_h
+#    undef connect
+#    define connect             connect_used_without_including_sys_socket_h
+#    undef accept
+#    define accept              accept_used_without_including_sys_socket_h
+#    undef bind
+#    define bind                bind_used_without_including_sys_socket_h
+#    undef getpeername
+#    define getpeername         getpeername_used_without_including_sys_socket_h
+#    undef getsockname
+#    define getsockname         getsockname_used_without_including_sys_socket_h
+#    undef getsockopt
+#    define getsockopt          getsockopt_used_without_including_sys_socket_h
+#    undef listen
+#    define listen              listen_used_without_including_sys_socket_h
+#    undef recv
+#    define recv                recv_used_without_including_sys_socket_h
+#    undef send
+#    define send                send_used_without_including_sys_socket_h
+#    undef recvfrom
+#    define recvfrom            recvfrom_used_without_including_sys_socket_h
+#    undef sendto
+#    define sendto              sendto_used_without_including_sys_socket_h
+#    undef setsockopt
+#    define setsockopt          setsockopt_used_without_including_sys_socket_h
+#    undef shutdown
+#    define shutdown            shutdown_used_without_including_sys_socket_h
+#   else
+     _GL_WARN_ON_USE (socket,
+                      "socket() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (connect,
+                      "connect() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (accept,
+                      "accept() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (bind,
+                      "bind() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (getpeername,
+                      "getpeername() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (getsockname,
+                      "getsockname() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (getsockopt,
+                      "getsockopt() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (listen,
+                      "listen() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (recv,
+                      "recv() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (send,
+                      "send() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (recvfrom,
+                      "recvfrom() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (sendto,
+                      "sendto() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (setsockopt,
+                      "setsockopt() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (shutdown,
+                      "shutdown() used without including <sys/socket.h>");
+#   endif
+#  endif
+#  if !defined _GL_SYS_SELECT_H
+#   if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#    undef select
+#    define select              select_used_without_including_sys_select_h
+#   else
+     _GL_WARN_ON_USE (select,
+                      "select() used without including <sys/select.h>");
+#   endif
+#  endif
+# endif
+#endif
+
+
 /* OS/2 EMX lacks these macros.  */
 #ifndef STDIN_FILENO
 # define STDIN_FILENO 0