tcp_select_server.c

select函数在linux下的应用

#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <netinet/in.h>
#include <sys/time.h>
#include <sys/select.h>

int time_out(int socket_id)
{
	struct timeval time_val;
	time_val.tv_sec=5;
	time_val.tv_usec=0;
	fd_set fd_array;
	FD_ZERO(&fd_array);
	FD_SET(socket_id,&fd_array);
	return select(socket_id+1,&fd_array,NULL,NULL,&time_val);
}

int main(int argc,char *argv[])
{
	int lisn_socket,client_socket;
	pid_t child;
	char buffer[512];
	int read_count=0;
	int opt=1;
	int select_return=0;
	int addr_len=sizeof(struct sockaddr);
	struct sockaddr_in addr_in,client_addr;
	memset(buffer,0,512);
	addr_in.sin_family=AF_INET;
	addr_in.sin_port=htons(5555);
	addr_in.sin_addr.s_addr=INADDR_ANY;
	lisn_socket=socket(AF_INET,SOCK_STREAM,0);
	setsockopt(lisn_socket,SOL_SOCKET,SO_REUSEADDR,&opt,sizeof(opt));
	if(bind(lisn_socket,(struct sockaddr *)&addr_in,sizeof(struct sockaddr))<0)
	{
		perror("bind");
		return -1;
	}
	listen(lisn_socket,10);
	while(1)
	{
		client_socket=accept(lisn_socket,(struct sockaddr *)&client_addr,&addr_len);
		child=fork();
		if(child==0)
		{
			close(lisn_socket);
			while(1)
			{
				select_return=time_out(client_socket);
				if(select_return>0)
				{
					read_count=read(client_socket,buffer,sizeof(buffer));
					write(client_socket,buffer,read_count);
					memset(buffer,0,sizeof(buffer));
				}
				else if(select_return==0)
				{
					close(client_socket);
					printf("client time out!\n");
					break;
				}
			}
			exit(0);
		}
		close(client_socket);
	}
	return 0;
}