New function to abstract SO_REUSEADDR.

svn:r1102

ChangeLog

@@ -141,6 +141,7 @@ Changes in current version:
  o New evthread_use_windows_threads() and evthread_use_pthreads() functions to set up the evthread callbacks with reasonable defaults.
  o Change the semantics of timeouts in conjunction with EV_PERSIST; timeouts in that case will now repeat until deleted.
  o sendfile, mmap and memory reference support for evbuffers.
+ o New evutil_make_listen_socket_reuseable() to abstract SO_REUSEADDR.
 
 Changes in 1.4.0:
  o allow \r or \n individually to separate HTTP headers instead of the standard "\r\n"; from Charles Kerr.

evutil.c

@@ -189,6 +189,21 @@ evutil_make_socket_nonblocking(evutil_socket_t fd)
 	return 0;
 }
 
+int
+evutil_make_listen_socket_reuseable(evutil_socket_t sock)
+{
+#ifndef WIN32
+	int one = 1;
+	/* REUSEADDR on Unix means, "don't hang on to this address after the
+	 * listener is closed."  On Windows, thoug, it means "don't keep other
+	 * processes from binding to this address while we're using it. */
+	return setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void*) &one,
+	    (socklen_t)sizeof(one));
+#else
+	return 0;
+#endif
+}
+
 ev_int64_t
 evutil_strtoll(const char *s, char **endptr, int base)
 {

include/event2/util.h

@@ -121,6 +121,16 @@ int evutil_socketpair(int d, int type, int protocol, evutil_socket_t sv[2]);
     @return 0 on success, -1 on failure
  */
 int evutil_make_socket_nonblocking(evutil_socket_t sock);
+
+/** Do platform-specific operations on a listener socket to make sure that
+    another program will be able to bind this address right after we've
+    closed the listener
+
+    @param sock The socket to make reuseabla
+    @return 0 on success, -1 on failure
+ */
+int evutil_make_listen_socket_reuseable(evutil_socket_t);
+
 #ifdef WIN32
 /** Do the platform-specific call needed to close a socket returned from
     socket() or accept(). */