Merge pull request #1911 from somdoron/FixUDPWindows

src/select.cpp

@@ -439,13 +439,24 @@ u_short zmq::select_t::get_fd_family (fd_t fd_)
 	sockaddr_storage addr = { 0 };
 	int addr_size = sizeof addr;
 
-    int rc = getsockname (fd_, (sockaddr *)&addr, &addr_size);
+    int type;
+    int type_length = sizeof(int);
+    
+    int rc = getsockopt(fd_, SOL_SOCKET, SO_TYPE, (char*) &type, &type_length);
+
+    if (rc == 0) {
+        if (type == SOCK_DGRAM)
+            return AF_INET;
+        else {
+            rc = getsockname(fd_, (sockaddr *)&addr, &addr_size);
 
             //  AF_INET and AF_INET6 can be mixed in select
             //  TODO: If proven otherwise, should simply return addr.sa_family
             if (rc != SOCKET_ERROR)
                 return addr.ss_family == AF_INET6 ? AF_INET : addr.ss_family;            
-    else
+        }
+    }    
+
     return AF_UNSPEC;    
 }