epoll

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epoll

epoll - I/O event notification facility

epoll is a variant of poll(2) that can be used either as an edge-triggered or a level-triggered interface and scales well to large numbers of watched file descriptors.

• epoll_create

#include <sys/epoll.h>

int epoll_create(int size);

size不用，0即可。

int epoll_create1(int flags);

• epoll_ctl

int epoll_ctl(int epfd, int op, int fd, struct_ epoll_event *event);

op: EPOLL_CTL_ADD, EPOLL_CTL_DEL, EPOLL_CTL_MOD;

typedef union epoll_data{

void *ptr;

int fd;

uint32_t u32;

uint64_t u64;

}epoll_data_t;

typedef epoll_event {

uint32_t events; /*Epoll events*/

epoll_data_t data;

};

events:EPOLLIN:可读；EPOLLOUT：可写；EPOLLET：边沿触发；EPOLLLT：水平触发（默认）。

The suggested way to use epoll as an edge-triggered (EPOLLET) interface is as follows:

          i   with nonblocking file descriptors; and

          ii  by waiting for an event only after  read(2) or write(2) return EAGAIN.

• epoll_wait

int epoll_wait(int epfd, struct epoll_event *events, int maxevents, int timeout);

int epoll_pwait(int epfd, struct epoll_event *events, int maxevents, int timeout, const sigset_t *sigmask);

timeout: -1死等；0，不等；>0,有限等待时间。

成功：事件个数，失败-1。

epoll

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原文地址：http://www.cnblogs.com/embedded-linux/p/5023862.html