linux socket聊天程序 （进程(fork)版本）

/**************************** client.c ********************************** */

#include<stdio.h>
#include<unistd.h>
#include<strings.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<netdb.h>

#define PORT 1234 /*listen port*/
#define MAXDATASIZE 100

int main ( int argc, char *argv[])
{
int sockfd, num;
pid_t pid;
char buf[MAXDATASIZE];
struct hostent *he;
struct sockaddr_in server;

if(argc!=2)
{
printf("usage %s<ip address>/n",argv[0]);
exit(1);
}
/*get ip address*/
if((he = gethostbyname(argv[1])) == NULL)
{
printf("gethostbyname error/n");
exit(1);
}
if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
{
printf("socket() error /n");
exit(1);
}

bzero(&server, sizeof(server));
server.sin_family = AF_INET;
server.sin_port = htons(PORT);
server.sin_addr = *((struct in_addr *)he->h_addr);

if(connect(sockfd, (struct sockaddr *)&server, sizeof(server)) == -1)
{
printf("connetc() error/n");
exit(1);
}
if((pid = fork()) >0)
{
while(1)
{
fgets(buf, MAXDATASIZE, stdin);
send(sockfd, buf, MAXDATASIZE, 0);

}
}
else if(pid == 0)
{ while(1)
{
recv(sockfd, buf, MAXDATASIZE, 0);
printf("server message: %s",buf);
}

}
else
return 1;

close(sockfd);
}

/*******************************************************/

/* server.c */

/******************************************************/

#include<stdio.h>
#include<strings.h>
#include<unistd.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>

#define PORT 1234
#define BACKLOG 1
#define MAXDATASIZE 100

void main()
{
int listenfd, connectfd;
struct sockaddr_in server;
struct sockaddr_in client;
socklen_t addrlen;
char buf[MAXDATASIZE];
pid_t pid;

if((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
{
perror("socket() error.");
exit(1);
}

int opt = SO_REUSEADDR;
setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));

bzero(&server, sizeof(server));
server.sin_family = AF_INET;
server.sin_port = htons(PORT);
server.sin_addr.s_addr = htonl(INADDR_ANY);
if(bind(listenfd, (struct sockaddr *)&server, sizeof(server)) == -1)
{
perror("bind() error.");
exit(1);
}
if(listen(listenfd, BACKLOG) == -1)
{
perror("listen() error.");
exit(1);
}

addrlen = sizeof(client);
while(1)
{
if((connectfd = accept(listenfd, (struct sockaddr *)&client, &addrlen )) == -1)
{
perror("accept() error.");
exit(1);
}
if((pid = fork()) >0)
{
while(1)
{
close(listenfd);
recv(connectfd, buf, MAXDATASIZE,0);
printf("the client says: %s/n",buf);
}

}
else if(pid == 0)
{
while(1)
{
close(listenfd);
fgets(buf, MAXDATASIZE, stdin);
send(connectfd, buf, MAXDATASIZE, 0);
}
}
else
return 1;
}
close(connectfd);
close(listenfd);
}