IO多路复用客户端-服务器模型

IO多路复用服务器 -- 实现字符回射

服务器端

/*************************************************************************
* File Name: select.c
* Author: Chen WenKe
* Email: chenwenke666@gmail.com
* Blog: https://caotanxiaoke.github.io
* Created Time: Mon 19 Jun 2017 03:42:26 AM PDT
*
* Description: 
    基于 IO 多路复用的回射 客户端-服务器。
 ************************************************************************/

#include "csapp.h"
void echo(int connfd);
void command(void);

int main(int argc, char **argv)
{
    int listenfd, connfd, port; 
    socklen_t clientlen = sizeof(struct sockaddr_in); 
    struct sockaddr_in clientaddr; 
    fd_set read_set, ready_set; 

    if (argc != 2)
    {
        fprintf(stderr, "usage: %s <port>
", argv[0]); 
        exit(0); 
    }
    port = atoi(argv[1]); 
    listenfd = Open_listenfd(port); 

    FD_ZERO(&read_set);     // clear the read set
    FD_SET(STDIN_FILENO, &read_set);    // Add stdin to read set
    FD_SET(listenfd, &read_set);    // Add listenfd to read set

    while(1)
    {
        ready_set = read_set; 
        Select(listenfd+1, &ready_set, NULL, NULL, NULL); 
        if (FD_ISSET(STDIN_FILENO, &ready_set))
            command();  // Read command line from stdin
        if (FD_ISSET(listenfd, &ready_set))
        {
            connfd = Accept(listenfd, (SA *)&clientaddr, &clientlen); 
            echo(connfd); 
            Close(connfd); 
        }
    }

}

void command(void)
{
    char buf[MAXLINE]; 
    if (!Fgets(buf, MAXLINE, stdin))
        exit(0);    // EOF
    printf("%s", buf);  // Process the input command. 
}

void echo(int connfd)
{
    int n; 
    char buf[MAXLINE]; 
    rio_t rio; 

    Rio_readinitb(&rio, connfd); 
    while (( n == Rio_readlineb(&rio, buf, MAXLINE)) != 0)
    {
        printf("server received %d bytes
", n); 
        Rio_writen(connfd, buf, n);
    }
}

##### 客户端

/*************************************************************************
* File Name: echoclient.c
* Author: Chen WenKe
* Email: chenwenke666@gmail.com
* Blog: https://caotanxiaoke.github.io
* Created Time: Sun 18 Jun 2017 08:00:49 PM PDT
*
* Description: 
    
 ************************************************************************/

#include "csapp.h"

int main(int argc, char **argv)
{
    int clientfd, port; 
    char *host, buf[MAXLINE];
    rio_t rio;

    if (argc != 3)
    {
        fprintf(stderr, "usage: %s <host> <port>
", argv[0]);
        exit(0); 
    }
    host = argv[1]; 
    port = atoi(argv[2]);

    clientfd = Open_clientfd(host, port); 
    Rio_readinitb(&rio, clientfd); 

    while (Fgets(buf, MAXLINE, stdin) != NULL)
    {
        Rio_writen(clientfd, buf, strlen(buf)); 
        Fputs(buf, stdout); 
    }
    Close(clientfd);
   exit(0);
}

[上面代码中所使用的头文件及编译方法](http://www.cnblogs.com/acm1314/p/5623562.html)