/* 相比于select与poll,epoll最大的好处是不会随着关心的fd数目的增多而降低效率 */ int main(void) { int count = 0; int listenfd; if ((listenfd = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) ERR_EXIT("socket"); struct sockaddr_in servaddr; memset(&servaddr, 0, sizeof(servaddr...
=AF_INET;address.sin_addr.s_addr=INADDR_ANY;address.sin_port=htons(PORT);//bind the socket to localhost port 8888if(bind(master_socket,(struct sockaddr*)&address,sizeof(address))<0){perror("bind failed");exit(EXIT_FAILURE);}printf("Listener on port %d \n",PORT);//try to specify ...
line88,in_runself._context.run(self._callback,*self._args)RuntimeError:cannot enter context:<_contextvars.Contextobjectat0x7f038b7ab540>isalready enteredExceptionincallback_SelectorSocketTransport._read_ready()handle:<Handle_SelectorSocketTransport._read_ready()>Traceback(most recent calllast):Fil...
socket. (A disk is not a slow device according to this definition.) If an I/O call on a slow device has already transferred some data by the time it is interrupted by a signal handler, then the call will return a success status (normally, the number of bytes transferred). *open(2)...
Re: Socket select call ? For a socket associated with a TCP connection a read return of zero indicates (as it does on virtually _all_ platforms) that the remote TCP has sent us a FINished segment meaning that we can expect to receive no more data from the remote. ...
select系统调用会返回已就绪的socket数目,但elect不会告诉我们,是哪几个socket已经就绪,我们还需要从头遍历,这很浪费时间。除此之外遍历set大小并不取决于一创建socket个数,而是取决于已创建的socket中的最大的fd. manual手册写的很清楚: The firstnfdsdescriptors are checked in each set; i.e., the descriptors...
select/epoll的好处就在于单个process就可以同时处理多个网络连接的IO。它的基本原理就是select,poll,epoll这个function会不断的轮询所负责的所有socket,当某个socket有数据到达了,就通知用户进程。( process blocks in call toselect, waiting foroneof possiblymany socketsto become readable)...
#include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <signal.h> #include <fcntl.h> #include <sys/wait.h> #include <sys/epoll.h> #include <stdlib.h> #include <stdio.h> #include <errno.h> #include <string.h> ...
2 Linux的socket 事件wakeup callback机制 言归正传,在介绍select、poll、epoll前,有必要说说linux(2.6+)内核的事件wakeup callback机制,这是IO多路复用机制存在的本质。Linux通过socket睡眠队列来管理所有等待socket的某个事件的process,同时通过wakeup机制来异步唤醒整个睡眠队列上等待事件的process,通知process相关事件发生...
$read= array($socket1,$socket2); $write=NULL; $except=NULL; $num_changed_sockets=socket_select($read,$write,$except,0); if ($num_changed_sockets===false) { /* Error handling */ } else if ($num_changed_sockets>0) { /* At least at one of the sockets something interesting happen...