多路复用I/O: socket编程之select(),poll(),epoll()
代码：
client.c
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/select.h>
#include <arpa/inet.h>
#include <assert.h>
#define maxn 1100
#define IP "127.0.0.1"
#define PORT 45178
#define MAXLINE 1024
#define LISTENQ 5
#define SIZE 10
#define BACKLOG 2
int main()
{
int sockfd;
if((sockfd = socket(AF_INET,SOCK_STREAM,)) == -)
{
printf("socket error!\n");
exit();
}
struct sockaddr_in server;
bzero(&server,sizeof(server));
server.sin_family = AF_INET;
server.sin_port = htons(PORT);
inet_pton(AF_INET,IP,&server.sin_addr);
char buf[maxn];
int connfd;
connfd = connect(sockfd,(struct sockaddr*)&server,sizeof(server));
if(connfd < )
{
printf("connect failure!\n");
return -;
}
printf("client send to server\n");
printf("please input something\n");
scanf("%s",buf);
write(sockfd,buf,maxn);
char recvbuf[maxn];
char sendbuf[maxn];
fd_set readfd;
int maxnum = ;
struct timeval T_time;
int n;
int sel_fd;
while()
{
FD_ZERO(&readfd);
FD_SET(sockfd,&readfd);
maxnum = sockfd;
T_time.tv_sec = ;
T_time.tv_usec = ;
sel_fd = select(maxnum + ,&readfd,NULL,NULL,&T_time);
if(sel_fd < )
{
continue;
}
else if(sel_fd == -)
{
printf("select error!\n");
return;
}
if(FD_ISSET(sockfd,&readfd))
{
n = read(sockfd,recvbuf,maxn);
if(n <= )
{
printf("server is closed!\n");
close(sockfd);
FD_CLR(sockfd,&readfd);
return;
}
printf("recv message is %s\n", recvbuf);
sleep();
write(sockfd,buf,strlen(buf) + );
}
}
close(sockfd);
return ;
}
server.c
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/select.h>
#include <arpa/inet.h>
#include <assert.h>
#define maxn 1100
#define PORT 45178
#define IP "127.0.0.1"
#define MAXLINE 1024
#define LISTENQ 5
#define SIZE 10
#define BACKLOG 2
typedef struct server_context_st
{
int cli_num; /*客户端个数*/
int cli_fds[SIZE]; /*客户端的个数*/
fd_set allfds; /*句柄集合*/
int maxfd; /*句柄最大值*/
} server_context_st; static int init();
static void deal_maxfd(int sockfd);
static int accept_client(int sockfd);
static void recv_client_msg(fd_set *readfd);
static void submit_client_msg(int temp,char buf[]);
static server_context_st *server_client = NULL;
int Max(int a,int b);
int Max(int a,int b)
{
return a>b?a:b;
}
static int server_init()
{
server_client = (server_context_st *)malloc(sizeof(server_context_st));
if(server_client == NULL)
{
return -;
}
memset(server_client,,sizeof(server_context_st));
int i=;
for(;i<SIZE;i++)
{
server_client->cli_fds[i] = -;
}
return ;
}
static int init()
{ int sockfd;
if((sockfd = socket(AF_INET,SOCK_STREAM,)) == -)
{
printf("socket error!\n");
exit();
}
int listenfd;
struct sockaddr_in server;
bzero(&server,sizeof(server));
server.sin_family = AF_INET;
server.sin_port = htons(PORT);
inet_pton(AF_INET,IP,&server.sin_addr);
if(bind(sockfd,(struct sockaddr*)&server,sizeof(struct sockaddr)) == -)
{
perror("bind error:");
return -;
}
listen(sockfd,BACKLOG);
return sockfd;
}
static void deal_maxfd(int sockfd)
{
fd_set *readfd = &server_client->allfds;
int sel_fd = ;
int clifd = -;
struct timeval T_time;
while()
{
FD_ZERO(readfd);
FD_SET(sockfd,readfd);
server_client->maxfd = sockfd;
T_time.tv_sec = ;
T_time.tv_usec = ; int i;
for(i=;i<server_client->cli_num;i++)
{
clifd = server_client->cli_fds[i];
FD_SET(clifd,readfd);
server_client->maxfd = Max(clifd,server_client->maxfd);
}
//retval = select(s_srv_ctx->maxfd + 1, readfds, NULL, NULL, &tv);
sel_fd = select(server_client->maxfd+,readfd,NULL,NULL,&T_time);
if(sel_fd == )
{
printf("time out!\n");
continue;
}
else if(sel_fd == -)
{
printf("something error!\n");
return ;
}
if(FD_ISSET(sockfd,readfd))
{
/*监听客户端请求*/
accept_client(sockfd);
}
else
{
/*接受处理客户端消息*/
recv_client_msg(readfd);
}
}
}
static int accept_client(int sockfd)
{
struct sockaddr_in server_c;
socklen_t len;
len = sizeof (server_c);
int afd = -;
Loop:
printf("waiting ............................\n");
afd = accept(sockfd,(struct sockaddr*)&server_c,&len);
if(afd == -)
{
if(errno == EINTR)
{
goto Loop;
}
else
{
fprintf(stderr, "accept fail,error:%s\n", strerror(errno));
return -;
}
}
printf("accept successful!\n");
int i=;
for(i=;i<SIZE;i++)
{
if(server_client->cli_fds[i] < )
{
server_client->cli_fds[i] = afd;
server_client->cli_num ++;
break;
}
}
if(i == SIZE)
{
printf("too many client to accept!\n");
return -;
}
}
static void recv_client_msg(fd_set *readfd)
{
int i=;
int temp;
char buf[maxn];
for(i=;i<server_client->cli_num;i++)
{
temp = server_client->cli_fds[i];
if(temp < )
{
continue;
}
if(FD_ISSET(temp,readfd))
{
int n = read(temp,buf,maxn);
if(n <= )
{
FD_CLR(temp,&server_client->allfds);
close(temp);
server_client->cli_fds[i] = -;
continue;
}
submit_client_msg(temp,buf);
}
}
}
static void submit_client_msg(int temp,char buf[])
{
assert(buf);
printf("receive message is %s\n",buf);
write(temp,buf,strlen(buf)+);
return ;
}
int main()
{
if(server_init() == -)
{
printf("init error\n");
return -;
}
int sockfd;
sockfd = init();
deal_maxfd(sockfd);
close(sockfd);
return ;
}
结果：