文章目录
一,poll
poll与select的区别
#define _GNU_SOURCE//POLLRDHUP的宏
#include<stdio.h>
#include<unistd.h>
#include<stdlib.h>
#include<string.h>
#include<poll.h>
#include<sys/socket.h>
#include<arpa/inet.h>
#include<netinet/in.h>
#include<assert.h>
#define MAX 10
int socket_init();
void poll_fds_init(struct pollfd fds[])//将整个数组全部清零
{
for(int i=0;i<MAX;++i)
{
fds[i].fd=-1;
fds[i].events=0;
fds[i].revents=0;
}
}
void poll_fds_add(int fd,struct pollfd fds[])
{
for(int i=0;i<MAX;++i)
{
if(fds[i].fd==-1)
{
fds[i].fd=fd;
fds[i].events=POLLIN;//读事件
fds[i].revents=0;//等到poll返回后poll会帮我们填充revents所以检查发生了哪些事件,就要检查revents中是否有我们注册的事件发生
break;
}
}
}
void poll_fds_del(int fd,struct pollfd fds[])
{
for(int i=0;i<MAX;++i)
{
if(fds[i].fd==fd)
{
fds[i].fd=-1;
fds[i].events=0;
fds[i].revents=0;
break;
}
}
}
int main()
{
int sockfd=socket_init();
assert(sockfd!=-1);
struct pollfd poll_fds[MAX];
poll_fds_init(poll_fds);//清空数组
poll_fds_add(sockfd,poll_fds);//
while(1)
{
int n=poll(poll_fds,MAX,5000);//5000mspoll以ms为单位
if(n<0)
{
printf("poll err\n");
}
else if(n==0)//poll返回值为0代表失败了
{
printf("time out\n");
}
else
{
for(int i=0;i<MAX;++i)//遍历数组
{
if(poll_fds[i].fd==-1)
{
continue;
}
//如果没有以下代码,客端关闭但是服务器端依旧判断该描述符上有读事件,
if(poll_fds[i].revents & POLLRDHUP)//真则说明客户端已断开
{
close(poll_fds[i].fd);
poll_fds_del(poll_fds[i].fd,poll_fds);
printf("client hup\n");
continue;
}
if(poll_fds[i].revents & POLLIN)//与,判断是否有读事件
{
if(poll_fds[i].fd==sockfd)
{
struct sockaddr_in caddr;//记录一个客户端ip接口的套接字地址结构
int len=sizeof(caddr);
int c=accept(sockfd,(struct sockaddr*)&caddr,&len);
if(c<0)
{
continue;
}
printf("accept :%d\n",c);
poll_fds_add(c,poll_fds);
}
else
{
char buff[128]={0};
int num=recv(poll_fds[i].fd,buff,127,0);
// int num=recv(poll_fds[i].fd,buff,1,0);
if(num<=0)
{
close(poll_fds[i].fd);
poll_fds_del(poll_fds[i].fd,poll_fds);
printf("client close\n");
}
else
{
printf("recv(%d)=%s\n",poll_fds[i].fd,buff);
send(poll_fds[i].fd,"ok",2,0);
}
}
}
//if(poll_fds[i].revents*POLLOUT)
}
}
}
}
int socket_init()
{
int sockfd=socket(AF_INET,SOCK_STREAM,0);
if(sockfd==-1)
{
return -1;
}
struct sockaddr_in saddr;
memset(&saddr,0,sizeof(saddr));
saddr.sin_family=AF_INET;
saddr.sin_port=htons(6000);
saddr.sin_addr.s_addr=inet_addr("127.0.0.1");
int res=bind(sockfd,(struct sockaddr*)&saddr,sizeof(saddr));
if(res==-1)
{
return -1;
}
res=listen(sockfd,5);
if(res==-1)
{
return -1;
}
return sockfd;
}
只接收一个数据时候的情况,和select情况一样,读了多少次就返回多少个OK
二,epoll
应对描述符多的
select,poll 与epoll的区别
day22
epoll代码
#include<stdio.h>
#include<unistd.h>
#include<stdlib.h>
#include<string.h>
#include<sys/select.h>
#include<sys/socket.h>
#include<arpa/inet.h>
#include<netinet/in.h>
#include<assert.h>
#include<sys/epoll.h>
#define MAX 10
int socket_init();
void epoll_add(int epfd,int fd)
{
struct epoll_event ev;
ev.data.fd=fd;
ev.events=EPOLLIN|EPOLLEY;//读事件
if(epoll_ctl(epfd,EPOLL_CTL_ADD,fd,&ev)==-1)
{
printf("epoll ctl add err\n");
}
}
void epoll_del(int epfd,int fd)
{
if(epoll_ctl(epfd,EPOLL_CTL_DEL,fd,NULL)==-1)
{
perror("epoll ctl del err\n");
}
}
int main()
{
int sockfd=socket_init();
assert(sockfd!=-1);
int epfd=epoll_create(MAX);//内核事件表
assert(epfd!=-1);
epoll_add(epfd,sockfd);将监听套接字添加到内核事件表
struct epoll_event evs[MAX];收集就绪描述符
while(1)
{
int n=epoll_wait(epfd,evs,MAX,5000);//阻塞获取就绪描述符
if(n==-1)
{
printf("epoll wait err\n");
}else if(n==0)
{
printf("time out\n");
}else
{
for(int i=0;i<n;++i)
{
int fd=evs[i].data.fd;
if(evs[i].events & EPOLLIN)//有读事件
{
if(fd==sockfd)
{
struct sockaddr_in caddr;
int len=sizeof(caddr);
int c=accept(sockfd,(struct sockaddr*)&caddr,&len);
if(c<0)
{
continue;
}
printf("accept c=%d\n",c);
epoll_add(epfd,c);
}else
{
char buff[128]={0};
int num=recv(fd,buff,127,0);
if(num<=0)
{//注意顺序,必须先移除fd(移除时用到了该文件描述符,所以不能先close(fd),但是select和poll不必在意),在关闭fd
epoll_del(epfd,fd);
close(fd);
printf("client close\n");
}else
{
printf("recv(%d)=%s\n",fd,buff);
send(fd,"ok",2,0);
}
}
}
}
}
}
}
int socket_init()
{
int sockfd=socket(AF_INET,SOCK_STREAM,0);
if(sockfd==-1)
{
return -1;
}
struct sockaddr_in saddr;
memset(&saddr,0,sizeof(saddr));
saddr.sin_family=AF_INET;
saddr.sin_port=htons(6000);
saddr.sin_addr.s_addr=inet_addr("127.0.0.1");
int res=bind(sockfd,(struct sockaddr*)&saddr,sizeof(saddr));
if(res==-1)
{
return -1;
}
res=listen(sockfd,5);
if(res==-1)
{
return -1;
]
return sockfd;
}
ET模式epoll代码
#include<stdio.h>
#include<unistd.h>
#include<stdlib.h>
#include<string.h>
#include<sys/select.h>
#include<sys/socket.h>
#include<arpa/inet.h>
#include<netinet/in.h>
#include<assert.h>
#include<sys/epoll.h>
#include<errno.h>
#define MAX 10
int socket_init();
void setnonblock(int fd)
{
int oldfl=fcntl(fd,F_GETFL);
int newfl=oldfl|O_NONBLOCK;//设置为阻塞,然后循环读取
if(fcntl(fd,F_SETFL,newfl)==-1)
{
printf("fcntl err\n");
}
}
void epoll_add(int epfd,int fd)
{
struct epoll_event ev;
ev.data.fd=fd;
ev.events=EPOLLIN|EPOLLEY;//读事件
//ev.events=EPOLLIN|EPOLLEY;//读事件|ET模式的设置
if(epoll_ctl(epfd,EPOLL_CTL_ADD,fd,&ev)==-1)
{
printf("epoll ctl add err\n");
}
setnonblock(fd);
}
void epoll_del(int epfd,int fd)
{
if(epoll_ctl(epfd,EPOLL_CTL_DEL,fd,NULL)==-1)
{
perror("epoll ctl del err\n");
}
}
int main()
{
int sockfd=socket_init();
assert(sockfd!=-1);
int epfd=epoll_create(MAX);//内核事件表
assert(epfd!=-1);
epoll_add(epfd,sockfd);将监听套接字添加到内核事件表
struct epoll_event evs[MAX];收集就绪描述符
while(1)
{
int n=epoll_wait(epfd,evs,MAX,5000);//阻塞获取就绪描述符
if(n==-1)
{
printf("epoll wait err\n");
}else if(n==0)
{
printf("time out\n");
}else
{
for(int i=0;i<n;++i)
{
int fd=evs[i].data.fd;
if(evs[i].events & EPOLLIN)//有读事件
{
if(fd==sockfd)
{
struct sockaddr_in caddr;
int len=sizeof(caddr);
int c=accept(sockfd,(struct sockaddr*)&caddr,&len);
if(c<0)
{
continue;
}
printf("accept c=%d\n",c);
epoll_add(epfd,c);
}else
{
while(1)
{
char buff[128]={0};
int num=recv(fd,buff,1,0)l
if(num==-1)
{
if(errno==EAGAINT ||erno== EWOULDBLOCK)//等于他就说明非阻塞模式下,没有可读的数据产生的错误
{
send(fd,"ok",2,0);
}
else
{
printf("recv err");
}
}
else if(num==0)
{
epoll_del(epdf,fd);
close(fd);
printf("client close\n");
break;
}
else
{
printf("buff=%s\n",buff);
}
}
}
}
}
}
}
}
int socket_init()
{
int sockfd=socket(AF_INET,SOCK_STREAM,0);
if(sockfd==-1)
{
return -1;
}
struct sockaddr_in saddr;
memset(&saddr,0,sizeof(saddr));
saddr.sin_family=AF_INET;
saddr.sin_port=htons(6000);
saddr.sin_addr.s_addr=inet_addr("127.0.0.1");
int res=bind(sockfd,(struct sockaddr*)&saddr,sizeof(saddr));
if(res==-1)
{
return -1;
}
res=listen(sockfd,5);
if(res==-1)
{
return -1;
]
return sockfd;
}