1     struct sockaddr_in localaddr;
 2     ///一定要给出结构体大小，要不然获取到的端口号可能是0
 3     socklen_t len = sizeof(localaddr);
　　　　///fd是创建的套接字
 4     int ret = getsockname(fd, (struct sockaddr*)&localaddr, &len);
 5 
 6     if(ret != 0)
 7     {
 8         perror("getsockname");
 9     }
10     else
11     {
12         perror("getsockname");
13         printf("port: %d\n", ntohs(localaddr.sin_port));
14     }