+ if (vector[0].buffer or vector[0].length)
+ {
+ return memcached_set_error(*instance->root, MEMCACHED_NOT_SUPPORTED, MEMCACHED_AT,
+ memcached_literal_param("UDP messages was attempted, but vector was not setup for it"));
+ }
+
+ struct msghdr msg;
+ memset(&msg, 0, sizeof(msg));
+
+ increment_udp_message_id(instance);
+ vector[0].buffer= instance->write_buffer;
+ vector[0].length= UDP_DATAGRAM_HEADER_LENGTH;
+
+ msg.msg_iov= (struct iovec*)vector;
+#if defined(TARGET_OS_OSX) && TARGET_OS_OSX
+ msg.msg_iovlen= int(count);
+#else
+ msg.msg_iovlen= count;
+#endif
+
+ uint32_t retry= 5;
+ while (--retry)
+ {
+ ssize_t sendmsg_length= ::sendmsg(instance->fd, &msg, 0);
+ if (sendmsg_length > 0)
+ {
+ break;
+ }
+ else if (sendmsg_length < 0)
+ {
+ if (errno == EMSGSIZE)
+ {
+ return memcached_set_error(*instance, MEMCACHED_WRITE_FAILURE, MEMCACHED_AT);
+ }
+
+ return memcached_set_errno(*instance, errno, MEMCACHED_AT);
+ }
+ }
+
+ return MEMCACHED_SUCCESS;