10-11-12 IO复用及select例子

1. 阻塞式IO



2. 非阻塞式IO



3. IO复用Select ／ epoll



4. 信号驱动IO



5. 异步IO



6. select示例

#include "socket_includes.h"

int mz_ipv4_tcp_create_socket(void)
{
int listenfd, sockfd, opt = 1;
struct sockaddr_in server, client;
socklen_t len;
int timep;
int ret;

listenfd = socket(AF_INET, SOCK_STREAM, 0);
if(listenfd < 0){
perror("Create socket fail.");
return -1;
}

if((ret = setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt))) < 0){
perror("Error, set socket reuse addr failed");
return -1;
}

bzero(&server, sizeof(server));
server.sin_family = AF_INET;
server.sin_port = htons(SERV_PORT);
server.sin_addr.s_addr = htonl(INADDR_ANY);

len = sizeof(struct sockaddr);
if(bind(listenfd, (struct sockaddr *)&server, len)<0){
perror("bind error.");
return -1;
}

listen(listenfd, MAX_LISTEN_QUE);

return listenfd;
}

int main(int argc, char *argv[])
{
int listenfd, sockfd;
struct sockaddr_in server, client;
socklen_t len;
int bytes =0 ;
fd_set global_rdfs,current_rdfs;
int maxfd;
int i;
char buf[MAX_BUFFER_SIZE];

len = sizeof(struct sockaddr_in);

listenfd = mz_ipv4_tcp_create_socket();
FD_ZERO(&global_rdfs);
FD_SET(listenfd, &global_rdfs);
maxfd = listenfd;

while(1){
current_rdfs = global_rdfs;
if(select(maxfd + 1, ¤t_rdfs, NULL, NULL, NULL)<0){
perror("select error.\n");
return RT_ERR;
}

for(i = 0; i <= maxfd; i++){

if(FD_ISSET(i, ¤t_rdfs)){
if(listenfd == i){
if((sockfd = accept(listenfd, (struct sockaddr*)&client, (socklen_t*)&len))<0){
perror("accept error.\n");
return RT_ERR;
}
printf("sockfd:%d\n", sockfd);
FD_CLR(i, ¤t_rdfs);
maxfd = maxfd > sockfd ? maxfd :sockfd;
FD_SET(sockfd, &global_rdfs);
}else{
printf("read socket:%d\n", i);
bytes = recv(i, buf, MAX_BUFFER_SIZE, 0);
if(bytes < 0){
perror("recv error.\n");
return RT_ERR;
}
if(bytes == 0){
FD_CLR(i, &global_rdfs);
close(i);
continue;
}
printf("buf:%s\n", buf);
send(i, buf, strlen(buf), 0);
}

}

}
}
}