epoll 使用实例

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EPOLL为我们带来了什么

#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>
#include <sys/time.h>
#include <signal.h>
#include <poll.h>
#include <sys/types.h>
#include <error.h>

void call_poll(void)
{
	struct pollfd fds;
	int32_t timeout_msecs = 5000;
	int err;
	
	fds.fd = 1;
	fds.events = POLLIN | POLLPRI ;
	err = poll( &fds, 1, timeout_msecs );
	if ( err > 0 ) {
		printf("Data is available now.\n");
	}
	else if ( err == 0 ) {
		printf("No data within five seconds.\n");
	}
	else  {
		perror( "poll()" );
	}

}
#include <sys/epoll.h>

void call_epoll(void)
{
	int epfd;
	struct epoll_event ev_stdin;
	int err;

	epfd = epoll_create(1);
	if ( epfd < 0 ) {
		perror( "epoll_create()" );
		return ;
	}

	bzero( &ev_stdin, sizeof( struct epoll_event) );
	ev_stdin.events = 
		//  available for read operations
		EPOLLIN | EPOLLPRI 
		// available for write operations
		// | EPOLLOUT 
		// Error condition && Hang up happened 
		| EPOLLERR | EPOLLHUP 
		// Sets the Edge Triggered behaviour 
		| EPOLLET 
		// Sets the one-shot behaviour. 
		// must call epoll_ctl with EPOLL_CTL_MOD to re-enable
		| EPOLLONESHOT 
		;

	err = epoll_ctl( epfd, EPOLL_CTL_ADD, 1, &ev_stdin );
	if ( err < 0 ) {
		perror( "epoll_ctl()" );
		goto _out;
	}
	err = epoll_wait( epfd, &ev_stdin, 1, 5000 );
	if ( err < 0 ) {
		perror( "epoll_wait()" );
	}
	else if ( err == 0 ) {
		printf("No data within five seconds.\n");
	}
	else {
		 printf("Data is available now.\n");
	}
	//err = epoll_ctl( epfd, EPOLL_CTL_DEL, 1, &ev_stdin );
	//
	err = epoll_ctl( epfd, EPOLL_CTL_DEL, 1, &ev_stdin );
	if ( err < 0 ) {
		perror( "epoll_ctl()" );
	}
_out:
	close( epfd );
}
int main ()
{
	call_epoll();
	return 0;
}