net程序，epoll示例程序——客户端

源码：

net程序。

#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <string.h>
#include <arpa/inet.h>
//这里配置服务器的ip地址和端口号
#define SERVER_LISTEN_PORT 3557
#define SERVER_HOST "192.168.1.202"#define  MAX_BUF_SIZE 1024
#define INVALID_SOCKET -1//返回值的宏定义，在开发linux环境时，用0表示成功
#define RES_SUC 0
#define RES_FAIL -1int main()
{//创建一个客户端socketint client_socket = INVALID_SOCKET;client_socket = socket(AF_INET, SOCK_STREAM, 0);if(INVALID_SOCKET == client_socket){printf("[main] create client socket fail!\n");return RES_FAIL;}//创建一个服务器端的地址结构体，用于存储socket要连接的服务器地址信息struct sockaddr_in serv_addr;serv_addr.sin_family = AF_INET;serv_addr.sin_addr.s_addr = inet_addr(SERVER_HOST);  // 指定服务程序的ip地址serv_addr.sin_port = htons(SERVER_LISTEN_PORT); //指定服务程序的端口//与服务器程序建立tcp连接if(connect(client_socket, (struct sockaddr*) &serv_addr, sizeof(serv_addr)) == RES_FAIL){printf("[main] connect to server %s:%d fail!\n", SERVER_HOST, SERVER_LISTEN_PORT);return RES_FAIL;}printf("[main] connect to server %s:%d suc!\n", SERVER_HOST, SERVER_LISTEN_PORT);//发送一条消息char write_buf[MAX_BUF_SIZE];memset(write_buf, '\0', MAX_BUF_SIZE);snprintf(write_buf, MAX_BUF_SIZE, "hello");if(write(client_socket, write_buf, MAX_BUF_SIZE) <= 0){printf("[main] write msg into socket:%d fail! content:[%s]!\n", client_socket, write_buf);return RES_FAIL;}printf("[main] send msg to server %s:%d suc!\n", SERVER_HOST, SERVER_LISTEN_PORT);//等待服务端的返回消息char read_buf[MAX_BUF_SIZE];memset(read_buf, '\0', MAX_BUF_SIZE);if (read(client_socket, read_buf, MAX_BUF_SIZE) > 0){printf("[main] recv responsed msg from socket:%d suc! content: %s\n", client_socket, read_buf);return RES_SUC;}else{printf("[main] recv responsed msg from socket:%d fail!\n", client_socket);return RES_FAIL;}}

已经有一个客户端程序正在运行。[root@clsserv202 echoserver]# gcc echo_client.c -o echo_client
[root@clsserv202 echoserver]# ./echo_client 
[main] connect to server 192.168.1.202:3557 suc!
[main] send msg to server 192.168.1.202:3557 suc!
[main] recv responsed msg from socket:3 suc! content:[hello]!