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     else11     {12         perror("getsockname");13         printf("port: %d\n", ntohs(localaddr.sin_port));14     }