说明

系统：ubuntu 14.04

安装库

sudo apt-get install libev-dev

可以在/usr/include下找到ev.h。

服务器代码

server.c

#include

#include

#include

#define PORT_NO 3033

#define BUFFER_SIZE 1024

int total_clients = 0; // Total number of connected clients

void accept_cb(struct ev_loop *loop, struct ev_io *watcher, int revents);

void read_cb(struct ev_loop *loop, struct ev_io *watcher, int revents);

int main()

{

struct ev_loop *loop = ev_default_loop(0);

int sd;

struct sockaddr_in addr;

int addr_len = sizeof(addr);

struct ev_io w_accept;

// Create server socket

if( (sd = socket(PF_INET, SOCK_STREAM, 0)) < 0 )

{

perror("socket error");

return -1;

}

bzero(&addr, sizeof(addr));

addr.sin_family = AF_INET;

addr.sin_port = htons(PORT_NO);

addr.sin_addr.s_addr = INADDR_ANY;

// Bind socket to address

if (bind(sd, (struct sockaddr*) &addr, sizeof(addr)) != 0)

{

perror("bind error");

}

// Start listing on the socket, backlog is 2

if (listen(sd, 2) < 0)

{

perror("listen error");

return -1;

}

// Initialize and start a watcher to accepts client requests

ev_io_init(&w_accept, accept_cb, sd, EV_READ);

ev_io_start(loop, &w_accept);

// Start infinite loop

while (1)

{

//ev_loop(loop, 0);

ev_run(loop, 0);

}

return 0;

}

/* Accept client requests */

void accept_cb(struct ev_loop *loop, struct ev_io *watcher, int revents)

{

struct sockaddr_in client_addr;

socklen_t client_len = sizeof(client_addr);

int client_sd;

struct ev_io *w_client = (struct ev_io*) malloc (sizeof(struct ev_io));

if(EV_ERROR & revents)

{

perror("got invalid event");

return;

}

// Accept client request

client_sd = accept(watcher->fd, (struct sockaddr *)&client_addr, &client_len);

if (client_sd < 0)

{

perror("accept error");

return;

}

total_clients ++; // Increment total_clients count

printf("Successfully connected with client.\n");

printf("%d client(s) connected.\n", total_clients);

// Initialize and start watcher to read client requests

ev_io_init(w_client, read_cb, client_sd, EV_READ);

ev_io_start(loop, w_client);

}

/* Read client message */

void read_cb(struct ev_loop *loop, struct ev_io *watcher, int revents){

char buffer[BUFFER_SIZE];

ssize_t read;

if(EV_ERROR & revents)

{

perror("got invalid event");

return;

}

// Receive message from client socket

read = recv(watcher->fd, buffer, BUFFER_SIZE, 0);

if(read < 0) // 出现错误

{

perror("read error");

return;

}

if(read == 0) // 有client关闭时

{

// Stop and free watchet if client socket is closing

ev_io_stop(loop,watcher);

free(watcher);

perror("peer might closing");

total_clients --; // Decrement total_clients count

printf("%d client(s) connected.\n", total_clients);

return;

}

else // 有数据到来

{

printf("message:%s\n",buffer);

}

// Send message bach to the client

send(watcher->fd, buffer, read, 0);

bzero(buffer, read);

}

当有客户端连接进来时，会调用accept_cb函数处理。当客户端有数据进来时，会调用read_cb来处理。

客户端代码

client.c

#include

#include

#define PORT_NO 3033

#define BUFFER_SIZE 1024

int main()

{

int sd;

struct sockaddr_in addr;

int addr_len = sizeof(addr);

char buffer[BUFFER_SIZE] = "";

// Create client socket

if( (sd = socket(PF_INET, SOCK_STREAM, 0)) < 0 )

{

perror("socket error");

return -1;

}

bzero(&addr, sizeof(addr));

addr.sin_family = AF_INET;

addr.sin_port = htons(PORT_NO);

addr.sin_addr.s_addr = htonl(INADDR_ANY);

// Connect to server socket

if(connect(sd, (struct sockaddr *)&addr, sizeof addr) < 0)

{

perror("Connect error");

return -1;

}

while (strcmp(buffer, "q") != 0)

{

// Read input from user and send message to the server

gets(buffer);

send(sd, buffer, strlen(buffer), 0);

// Receive message from the server

recv(sd, buffer, BUFFER_SIZE, 0);

printf("message: %s\n", buffer);

}

return 0;

}

编译测试

gcc server.c -o server -lev

gcc client.c -o client

可以同时启动多个client。