原生epoll一共只有三個庫函式介面，已經足夠簡潔，但具體使用上各種程式碼實現依舊千差萬別，這裡對epoll做了個簡單的介面封裝，以供參考，本人水平有限，不足之處歡迎指教。

程式碼如下：

event_epoll.h

#ifndef EVENT_EPOLL_H_
#define EVENT_EPOLL_H_

#include <functional>
#include <sys/epoll.h>


class Epoll
{
private:
    typedef std::function<void (int fd, void *ctx, int revents)> event_handler;

    struct fd_node
    {
        fd_node(): fd(-1), ctx(NULL), handler(NULL) {}
        int fd;
        void *ctx;
        event_handler handler;
    };

public:
    Epoll(): epoll_fd_(-1), maxfds_(-1), fd_nodes_(NULL), epoll_events_(NULL) {}

public:
    int Init(int maxfds);
    int Free();

    int Register(int fd, event_handler handler, void *ctx);
    int Unregister(int fd);
    int EventAdd(int fd, int events);
    int EventDel(int fd);
    int Poll(int timeout_ms);

private:
    int epoll_fd_;
    int maxfds_;
    fd_node **fd_nodes_;
    epoll_event *epoll_events_;
};

#endif /*EVENT_EPOLL_H_*/

 

#include <unistd.h>
#include <string.h>
#include "event_epoll.h"


int Epoll::Init(int maxfds)
{
    epoll_fd_ = epoll_create(maxfds);

    if (-1 == epoll_fd_) return -1;

    maxfds_ = maxfds;
    fd_nodes_ = new fd_node *[maxfds];
    epoll_events_ = new epoll_event[maxfds];

    return 0;
}

int Epoll::Free()
{
    close(epoll_fd_);

    delete epoll_events_;

    for (int i = 0; i < maxfds_; i++)
    {
        if (fd_nodes_[i]) delete fd_nodes_[i];
    }

    delete []fd_nodes_;

    return 0;
}

int Epoll::Register(int fd, event_handler handler, void *ctx)
{
    fd_node *fdn;

    if (fd >= maxfds_) return -1;

    fdn = new fd_node;
    fdn->handler = handler;
    fdn->fd = fd;
    fdn->ctx = ctx;

    fd_nodes_[fd] = fdn;

    return 0;
}

int Epoll::Unregister(int fd)
{
    if (fd >= maxfds_) return -1;

    delete fd_nodes_[fd];
    fd_nodes_[fd] = NULL;

    return 0;
}

int Epoll::EventAdd(int fd, int events)
{
    fd_node *fdn;
    struct epoll_event ep;

    if (fd >= maxfds_) return -1;

    fdn = fd_nodes_[fd];
    ep.events = events;
    ep.data.ptr = fdn;

    if (0 != epoll_ctl(epoll_fd_, EPOLL_CTL_ADD, fd, &ep))
    {
        return -1;
    }

    return 0;
}

int Epoll::EventDel(int fd)
{
    struct epoll_event ep;

    if (0 != epoll_ctl(epoll_fd_, EPOLL_CTL_DEL, fd, &ep))
    {
        return -1;
    }

    return 0;
}

int Epoll::Poll(int timeout_ms)
{
    int n;
    int events;
    fd_node *fdn;

    n = epoll_wait(epoll_fd_, epoll_events_, maxfds_, timeout_ms);

    for (int i = 0; i < n; i++)
    {
        events = epoll_events_[i].events;
        fdn = (fd_node *)epoll_events_[i].data.ptr;

        fdn->handler(fdn->fd, fdn->ctx, events);
    }

    return n;
}