复件 server2.c

linux系统下

#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <netinet/in.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/time.h>
//////////////////////////////////////////////////////////////
int main()
{
int server_sockfd, client_sockfd;
int server_len, client_len;
int fd_max=0;
struct sockaddr_in server_address;
struct sockaddr_in client_address;
int result;
fd_set readfds, testfds;

server_sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (server_sockfd > fd_max)
	fd_max = server_sockfd+1;
//printf("fd_max is %d",fd_max);
server_address.sin_family = AF_INET;
server_address.sin_addr.s_addr =htonl(INADDR_ANY); 
server_address.sin_port = htons(9734);
server_len = sizeof (server_address);

bind(server_sockfd, (struct sockaddr *)&server_address, server_len);

listen(server_sockfd,5);

FD_ZERO(&readfds);
FD_SET(server_sockfd, &readfds);

while(1)
{
	char ch;
	int fd;
	int nread;

	testfds = readfds;

	printf("server waiting\n");
printf("start select!\n");
	result = select(fd_max, &testfds, (fd_set *)0,
		(fd_set* )0, (struct timeval*) 0);
printf("select end!\n");
	if (result<1)
	{
		perror("server2");
		exit(1);
	}
//printf("FD_SETSIZE is %d\n",FD_SETSIZE);
	for (fd=0;fd<=fd_max;fd++)
	{
printf(" %d ",fd);
	if(FD_ISSET(fd,&testfds))
	{
		if(fd == server_sockfd)
		{
printf("fd == server_sockfd,fd is %d)\n",fd);
			client_len = sizeof(client_address);
//printf("start accept!\n");
			client_sockfd = accept(server_sockfd,
				(struct sockaddr*)&client_address,
				&client_len);
			if(fd_max<=client_sockfd)
				fd_max = client_sockfd+1;
//printf("end of accept!\n");
			FD_SET(client_sockfd, &readfds);
			printf("adding client on fd %d\n",client_sockfd);
		}
		else 
		{
printf("this is client socket\n");
			ioctl(fd,FIONREAD,&nread);
			if (nread == 0)
			{
printf(" (nread ==0)");
				close(fd);
				FD_CLR(fd,&readfds);
				printf("removing client on fd %d\n",fd);
			}
			else
			{
printf("start read and sleep! fd is %d\n",fd);
				read(fd, &ch, 1);
				sleep(5);
printf("end of read and sleep\n");
				printf("serving client on fd %d\n",fd);
				ch++;
				write(fd, &ch, 1);
			}
		}
	}//if
	}//for
}
}

//end of file