socket的accept: Invalid argument问题

 1 void local_sdk_server::wait_remote_client_connect_and_comm()
 2 {
 3     /*服务器服务启动，等待客户端的链接的到来*/
 4     //sockaddr_in client_addr;
 5     sockaddr client_addr;
 6     socklen_t len;
 7     user users;//client
 8     string operation_key;
 9     string operation_value;
10     ROS_INFO( "Watting connect......................." );
11     len = 1;
12     int accept_fd = accept( listen_fd, &client_addr, &len );
13     if( accept_fd < 0 )
14     {
15         ROS_ERROR("errno is %s",strerror(errno));
16         ROS_ERROR("accept failed accept_fd is %d", accept_fd);
17     }
18     if( accept_fd >= 0 )//用户连接成功,返回的新的文件描述符
19     {
20         ROS_INFO( "accept_fd: %d", accept_fd );