multiplexed I/O Model poll () Model Code implementation

multiplexed I/O Model poll () Model Code implementation

The poll () mechanism is similar to the select () mechanism, and is a way to poll multiple descriptors.

The difference is that poll () does not have a limit on the number of descriptors.

is to poll each descriptor with a struct POLLFD struct.

struct POLLFD Fdarray

{

int FD; /* File Descriptor */

Short events; /* Indicates the awaited event */

Short revents;/* represents an event that actually occurs when the event is returned */

};

Data.h

#ifndef data_h#defineData_h#include<string.h>#include<stdio.h>#include<poll.h>#include<sys/types.h>#include<sys/stat.h>#include<stdlib.h>#include<errno.h>#include<netinet/inch.h>#include<sys/socket.h>#include<sys/Select.h>#include<arpa/inet.h>#include<assert.h>#include<unistd.h>#defineMAXN 1100#defineMAXLINE 10#defineLISTEN 10#defineIP "127.0.0.1"#definePORT 4578#defineBACKLOG 5#defineINFTIM-1#endif

Server.c

1#include"data.h"2 Static voidDeal_message (structPOLLFD *fd_array,intnum);3 Static voidPoll_accept (intsockfd);4 5 Static intInit ()6 {7     structsockaddr_in server_in;8     intsockfd;9     if(SOCKFD = socket (Af_inet,sock_stream,0)) == -1)Ten     { Onefprintf (stderr,"socket Fail,error:%s\n", Strerror (errno)); A         return-1; -     } -Bzero (&server_in,sizeof(server_in)); theserver_in.sin_family =af_inet; -Server_in.sin_port =htons (PORT); -Inet_pton (af_inet,ip,&server_in.sin_addr); -     if(Bind (SOCKFD, (structsockaddr*) &server_in,sizeof(structSOCKADDR)) = =-1) +     { -fprintf (stderr,"bind fail,error:%s\n", Strerror (errno)); +         return-1; A     } at Listen (sockfd,backlog); -     returnsockfd; - } -  - Static voidPoll_accept (intsockfd) - { in     structPOLLFD FD_ARRAY[MAXN]; -     intAfD; to     intPOLLFD; +     structsockaddr_in client_in; -Bzero (&client_in,sizeof(client_in)); the     inti =0; *fd_array[0].FD =sockfd; $fd_array[0].events =Pollin;Panax Notoginseng      for(i=0; i<maxn;i++) -     { theFD_ARRAY[I].FD =-1; +     } A     intnum =0; the     intLen =sizeof(client_in); +      while(1) -     { $          $POLLFD = Poll (fd_array,num+1, Inftim); -         if(POLLFD = =-1) -         { thefprintf (stderr,"Poll Fail,error%s\n", Strerror (errno)); -             return;Wuyi         } the         if(POLLFD = =0) -         { Wu             Continue; -         } About         if(fd_array[0].revents &pollout) $         { -             if(AfD = Accept (SOCKFD, (structsockaddr*) (&client_in,&len)) = =-1) -             { -fprintf (stderr,"Accept fail,error:%s\n", Strerror (errno)); A                 return ; +             } the         } -i =0; $          for(i =0; i<maxn;i++) the         { the             if(Fd_array[i].fd <0) the             { theFD_ARRAY[I].FD =AfD; -                  Break; in             } the         } the         if(i = =MAXN) About         { theprintf"too many to server!\n"); the             return ; the         } +Fd_array[i].events =Pollin; -         if(I >num) thenum =i;Bayi         if(--POLLFD <=0) the             Continue; the     } - deal_message (fd_array,num); - } the  the Static voidDeal_message (structPOLLFD *fd_array,intnum) the { the     intI,n; -     CharBUF[MAXN]; thememset (BUF,' /',sizeof(BUF)); the      for(i=1; i<=num;i++) the     {94         if(Fd_array[i].fd <0) the             Continue; the         if(fd_array[i].revents&Pollin) the         {98n =read (FD_ARRAY[I].FD,BUF,MAXN); About             if(n = =0) -             {101 Close (FD_ARRAY[I].FD);102FD_ARRAY[I].FD =-1;103                 Continue;104             } the write (stdout_fileno,buf,n);106 write (fd_array[i].fd,buf,n);107         }108     }109 } the intMain ()111 { the     intSOCKFD =init ();113 poll_accept (SOCKFD); the Close (SOCKFD); the     return 0; the}

multiplexed I/O Model poll () Model Code implementation