服务器客户端多进程

#include 
#include 
#include 
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#include 
#define SRV_PORT 9999
int main(int argc,char **argv){
	int lfd,cfd;
	pid_t pid;
	struct sockaddr_in serv_addr,cli_addr;
	socklen_t cli_addr_len;
	char buf[BUFSIZE];
	int n,i;
	bzero(&serv_addr,sizeof(sercv_addr));
	serv_addr.sin_family=AF_INET;
	serv_addr.sin_addr.s_addr=htonl(INADDR_ANY);
	serv_addr.sin_port=htons(SERV_PORT);
	lfd=socket(AF_INET,SOCK_STREAM,0);
	Bind(lfd,(struct sockaddr*)&serv_addr,sizeof(serv_addr));
	Listen(lfd,128);
	cli_addr_len=sizeof(cli_addr);
	while(1){
		cfd=Accept(lfd,(struct sockaddr*)&cli_addr,sizeof(cli_addr));
		pid=fork();
		if(pid<0){
			perror("fork error");
		}else if(pid==0){
			close(lfd);
			break;
		}else{
			close(cfd);
			continue;
		}
	}
	if(pid==0){
		for(;;){
			n=Read(cfd,buf,sizeof(buf));
			if(n==0){
				close(cfd);
				exit(1);
			}
			for(i=0;i 
会出现僵尸进程，父进程由于阻塞所以没能回收子进程。利用信号来解决：
 这样，当子进程退出时，父进程收到信号，就会去回收子进程了，不会出现僵尸进程
 
#include 
#include 
#include 
#include 
#include 
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#include 

#define SRV_PORT 9999
void catch_child(int signum){
	while((waitpid(0,NULL,WNOHANG))>0);
	return;
}

int main(int argc,char **argv){
	int lfd,cfd;
	pid_t pid;
	struct sockaddr_in serv_addr,cli_addr;
	socklen_t cli_addr_len;
	char buf[BUFSIZE];
	int n,i;
	bzero(&serv_addr,sizeof(sercv_addr));
	serv_addr.sin_family=AF_INET;
	serv_addr.sin_addr.s_addr=htonl(INADDR_ANY);
	serv_addr.sin_port=htons(SERV_PORT);
	lfd=socket(AF_INET,SOCK_STREAM,0);
	Bind(lfd,(struct sockaddr*)&serv_addr,sizeof(serv_addr));
	Listen(lfd,128);
	cli_addr_len=sizeof(cli_addr);
	while(1){
		cfd=Accept(lfd,(struct sockaddr*)&cli_addr,sizeof(cli_addr));
		pid=fork();
		if(pid<0){
			perror("fork error");
		}else if(pid==0){
			close(lfd);
			break;
		}else{
			struct sigaction act;
			act.sa_handler=catch_child;
			sigemptyset(&act.sa_mask);
			act.sa_flags=0;
			n=sigaction(SIGCHILD,&act,NULL);
			if(n!=0){
				perror("sigaction error");
			}

			close(cfd);
			continue;
		}
	}
	if(pid==0){
		for(;;){
			n=Read(cfd,buf,sizeof(buf));
			if(n==0){
				close(cfd);
				exit(1);
			}
			for(i=0;i