Program Description: multi-process concurrency. When a request is received, fork processes close the connection socket for the parent process, and the sub-process closes the listening socket, each new accept request is executed by the sub-process, and the parent process continues listen.
/*************************************** ************************************ Author: denny wqf363@hotmail.com 2006 * Desc: multi-process concurrency * seat uming: All programs do not need, is garbage, 80% of the time to do 20% of the thing. (Program efficiency) **************************************** * ***********************************/# include <sys/types. h> # include <sys/socket. h> # include <netinet/in. h> # include <ARPA/inet. h> # include <netdb. h> # include <stdio. h> # include <unistd. h> # include <errno. h> # include <string. h> # include <pthread. h> # include <malloc. h> # include <stdlib. h> # define backlog 5 # define maxdatasize 1000 # Define Port 1234 void process_cl I (INT, sockaddr_in); int main (INT argc, char * argv []) // requires a parameter port number {int listenfd, // listen to socket sock connectfd; // new socket struct sockaddr_in servaddr received by accept, // cliaddr server address; // client address socklen_t adrlen; // sockaddr address length int servport; // server listening port number pid_t PID; // obtain the port number of the server listener if (argc! = 2) {printf ("Usage: % s portnumber/A/N", argv [0]); return 1 ;} if (servport = atoi (argv [1]) <0) {printf ("Usage: % s portnumber/A/N", argv [0]); return 1;}/* the server starts to establish the socket descriptor */If (listenfd = socket (af_inet, sock_stream, 0) =-1) {fprintf (stderr, "socket error: % s/n/a", strerror (errno); return 1;}/* set the parameters in the socket address structure servaddr and bind the server port number */servaddr. sin_family = af_inet; servaddr. sin_addr.s_addr = htonl (inaddr_any); servaddr. sin_port = htons (servport); If (BIND (listenfd, (struct sockaddr *) & servaddr, sizeof (servaddr) <0) {printf ("BIND error: % s/n/a ", strerror (errno); exit (2);}/* listen to sockfd descriptor */If (Listen (listenfd, backlog) =-1) {printf ("Listen error: % s/n/a", strerror (errno); exit (3) ;}while (1) {printf ("% s: waiting for data on port tcp % u/N ", argv [0], servport); adrlen = sizeof (struct sockaddr_in); connectfd = accept (listenfd, (struct sockaddr *) & cliaddr, & adrlen); If (connectfd <0) {perror ("accetp () Error/N"); exit (4 );} // use multi-process if (pid = fork ()> 0) {close (connectfd); continue;} else if (pid = 0) {close (listenfd ); process_cli (connectfd, cliaddr); exit (0);} else {printf ("fork () error. /n "); exit (0);} Close (listenfd);} void process_cli (INT connectfd, sockaddr_in client ){//.... close (connectfd );}
