聊天程序的简单实现

功能:

实现两个主机之间的局域网聊天

实现关键:

如何同时处理套接字的输入和标准输入 --- select函数

客户端的程序

#include "unp.h"
void cli_echo(FILE *fp, int sockfd)
{
	int maxfdp1, stdineof;
	fd_set rset;
	char buf[1000];
	int n;
	stdineof=0;
	FD_ZERO(&rset);
	for(;;){
		if(stdineof==0)
			FD_SET(fileno(fp),&rset);
		FD_SET(sockfd,&rset);
		maxfdp1=max(fileno(fp), sockfd)+1;
		Select(maxfdp1, &rset, NULL, NULL, NULL);
		if(FD_ISSET(sockfd, &rset)) {//socket is readable
			if( (n=Read(sockfd, buf, 1000))==0){
				if(stdineof==1)
					return;//normal termination
				else
					err_quit("cli_echo: server terminated prematurely");
			}
			Write(fileno(stdout),buf,n);			
		}
		if(FD_ISSET(fileno(fp), &rset)){//input is readable
			if( (n=Read(fileno(fp),buf,1000))==0){
				stdineof=1;
				Shutdown(sockfd, SHUT_WR);
				FD_CLR(fileno(fp), &rset);
				continue;
			}
			Writen(sockfd, buf, n);
		}
	}
}
int
main(int argc, char **argv)
{
	int sockfd;
	struct sockaddr_in servaddr;
	if(argc!=2)
		err_quit("usage: tcpcli <IPaddress>");
	
	sockfd=Socket(AF_INET, SOCK_STREAM, 0);
	
	bzero(&servaddr, sizeof(servaddr));
	servaddr.sin_family=AF_INET;
	servaddr.sin_port=htons(1234);
	Inet_pton(AF_INET,argv[1], &servaddr.sin_addr);
	Connect(sockfd, (SA*) &servaddr, sizeof(servaddr));
	cli_echo(stdin,sockfd);
	exit(0);
}

服务器端的程序

#include "unp.h"
#include <time.h>
void srv_echo(FILE *fp, int sockfd)
{
	int maxfdp1, stdineof;
	fd_set rset;
	char buf[1000];
	int n;
	stdineof=0;
	FD_ZERO(&rset);
	for(;;){
		if(stdineof==0)
			FD_SET(fileno(fp),&rset);
		FD_SET(sockfd,&rset);
		maxfdp1=max(fileno(fp), sockfd)+1;
		Select(maxfdp1, &rset, NULL, NULL, NULL);
		if(FD_ISSET(sockfd, &rset)) {//socket is readable
			if( (n=Read(sockfd, buf, 1000))==0){
				if(stdineof==1)
					return;//normal termination
				else
					err_quit("srv_echo: client terminated prematurely");
			}
			Write(fileno(stdout),buf,n);			
		}
		if(FD_ISSET(fileno(fp), &rset)){//input is readable
			if( (n=Read(fileno(fp),buf,1000))==0){
				stdineof=1;
				Shutdown(sockfd, SHUT_WR);
				FD_CLR(fileno(fp), &rset);
				continue;
			}
			Writen(sockfd, buf, n);
		}
	}
}
int 
main(int argc, char **argv)
{
	int i, maxi, maxfd, listenfd, connfd, sockfd;
	socklen_t clilen;
	struct sockaddr_in cliaddr, servaddr;
	listenfd = Socket(AF_INET, SOCK_STREAM,0);
	bzero(&servaddr, sizeof(servaddr));
	servaddr.sin_family=AF_INET;
	servaddr.sin_addr.s_addr=htonl(INADDR_ANY);
	servaddr.sin_port=htons(1234);
	Bind(listenfd, (SA*)&servaddr, sizeof(servaddr));
	Listen(listenfd, LISTENQ);
	clilen=sizeof(cliaddr);
	connfd=Accept(listenfd, (SA*) &cliaddr, &clilen);
	
	srv_echo(stdin,connfd);
	
	Close(connfd);
	return 0;
}

实现结果:

1. 先开启服务端 ./srv_echo

2. 再开启客户端 ./cli_echo 127.0.0.1

3. 任意在服务端或者客户端输入内容, 对端都将收到该内容

来自为知笔记(Wiz)

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