epoll示例程序——客户端

源码：

#include 
#include 
#include 
#include 
#include 
//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 -1

int main()
{
	//创建一个客户端socket
	int 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;
	}
	
}

按照如下方式编译和执行：

[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]!