TCP网络编程中多线程的客户端实现（linux下）

TCP网络编程中多线程的客户端实现（linux下）

示例如下：

#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <errno.h>
#include <strings.h>
#include <ctype.h>
#include <sys/wait.h>
#include <signal.h>

void sig_child(int signo)
{
while(waitpid(-1,NULL,WNOHANG) > 0);
return ;
}

int port = 8000;
int main()
{
struct sockaddr_in sin,pin;
int sock_descriptor,temp_sock_descriptor;
socklen_t address_size;
int i ,len,pid,on =1;
char buf[16384];

signal(SIGCHLD,sig_child);

sock_descriptor = socket(AF_INET,SOCK_STREAM,0);
bzero(&sin,sizeof(sin));
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = INADDR_ANY;
sin.sin_port = htons(port);
setsockopt(sock_descriptor,SOL_SOCKET,SO_REUSEADDR,&on,sizeof(on));
if( bind(sock_descriptor,(struct sockaddr *)&sin,sizeof(sin)) == -1 )
{
perror("call to bind\n");
exit(1);
}
if(listen(sock_descriptor,20) == -1)
{
perror("call to listen\n");
exit(1);
}
printf("accepting connections...\n");

while(1)
{
temp_sock_descriptor = accept(sock_descriptor,(struct sockaddr *)&pin,&address_size);
if( (pid = fork()) < 0 )
{
perror("fork");
exit(1);
}
else if(pid == 0)
{//child
close(sock_descriptor);
if(recv(temp_sock_descriptor,buf,16384,0) == -1)
{
perror("call to recv\n");
exit(1);
}
printf("received from client :%s\n",buf);

len = strlen(buf);
for( i  = 0 ; i < len ; i++)
{
buf[i] = toupper(buf[i]);
}
if(send(temp_sock_descriptor,buf,len+1,0) == -1)
{
perror("call to send \n");
exit(1);
}
sleep(60);
close(temp_sock_descriptor);
exit(0);
}
close(temp_sock_descriptor);
}

}

注意：

1、由于父进程并不需要连接套接字，所以需要在父进程中关闭。同理，子进程不需要监听套接字，因此在子进程中关闭。

2、子进程在结束时会向父进程递送SIGCHLD信号，所以在父进程中捕获SIGCHLD信号，并在该信号处理程序中调用waitpid，从而防止僵尸进程的产生。