Linux io mode and select, poll, Epoll detailed

Original: 1190000003063859

I've only extracted the Epoll code example, the server-side code

#defineIPADDRESS "127.0.0.1"#definePORT 8787#defineMAXSIZE 1024#defineListenq 5#defineFdsize 1000#defineEpollevents 100LISTENFD=Socket_bind (ipaddress,port);structepoll_event events[epollevents];//Create a descriptorEPOLLFD =epoll_create (fdsize);//Adding a Listener descriptor eventadd_event (Epollfd,listenfd,epollin);//Loop Wait for ( ; ; ) {    //The function returns the number of descriptor events that have been preparedret = epoll_wait (epollfd,events,epollevents,-1); //processing the received connectionhandle_events (EPOLLFD,EVENTS,RET,LISTENFD,BUF);}//event handler functionStatic voidHandle_events (intEPOLLFD,structEpoll_event *events,intNumintLISTENFD,Char*buf) {     inti; intFD; //to traverse, as long as the prepared IO events are traversed. Num was not fdsize at the time of Epoll_create.       for(i =0; I < num;i++) {FD=EVENTS[I].DATA.FD; //processing based on the type and event type of the descriptor         if(FD = = LISTENFD) && (Events[i].events &Epollin))         Handle_accpet (EPOLLFD,LISTENFD); Else if(Events[i].events &Epollin) Do_read (EPOLLFD,FD,BUF); Else if(Events[i].events &epollout) Do_write (EPOLLFD,FD,BUF); }}//Add EventStatic voidAdd_event (intEPOLLFD,intFdintState ) {    structepoll_event ev; Ev.events=State ; EV.DATA.FD=FD; Epoll_ctl (EPOLLFD,EPOLL_CTL_ADD,FD,&ev);}//handles the received connection. Add a file descriptor to the Epoll monitoring queueStatic voidHandle_accpet (intEPOLLFD,intLISTENFD) {     intCLIFD; structsockaddr_in cliaddr;          Socklen_t Cliaddrlen; CLIFD= Accept (LISTENFD, (structsockaddr*) &cliaddr,&Cliaddrlen); if(CLIFD = =-1) perror ("Accpet Error:"); Else{printf ("accept a new client:%s:%d\n", Inet_ntoa (CLIADDR.SIN_ADDR), cliaddr.sin_port);//Add a customer descriptor and eventadd_event (Epollfd,clifd,epollin); } }//Read ProcessingStatic voidDo_read (intEPOLLFD,intFdChar*buf) {    intnread; Nread=read (fd,buf,maxsize); if(Nread = =-1) {perror ("Read error:"); Close (FD); //remember the close FDDelete_event (Epollfd,fd,epollin);//Delete Listener    }    Else if(Nread = =0) {fprintf (stderr,"Client close.\n"); Close (FD); //remember the close FDDelete_event (Epollfd,fd,epollin);//Delete Listener    }         Else{printf ("Read message is:%s", BUF); //modifies the event corresponding to the descriptor, changed from read to writemodify_event (epollfd,fd,epollout); } }//Write ProcessingStatic voidDo_write (intEPOLLFD,intFdChar*buf) {         intNwrite; Nwrite=Write (Fd,buf,strlen (BUF)); if(Nwrite = =-1) {perror ("Write Error:");   Close (FD); //remember the close FDDelete_event (epollfd,fd,epollout);//Delete Listener}Else{modify_event (Epollfd,fd,epollin); } memset (BUF,0, MAXSIZE); }//Delete EventStatic voidDelete_event (intEPOLLFD,intFdintState ) {    structepoll_event ev; Ev.events=State ; EV.DATA.FD=FD; Epoll_ctl (EPOLLFD,EPOLL_CTL_DEL,FD,&ev);}//Modifying EventsStatic voidModify_event (intEPOLLFD,intFdintState ) {         structepoll_event ev; Ev.events=State ; EV.DATA.FD=FD; Epoll_ctl (EPOLLFD,EPOLL_CTL_MOD,FD,&ev);}//Note: I'll save the other end.

Linux io mode and select, poll, epoll details (RPM)