libevent源碼分析-介紹、安裝、使用
阿新 • • 發佈：2017-07-21
ont write net clas pretty string his har oot
- Libevent介紹
- 安裝
- 樣例
Libevent介紹
在include\event2\event.h中有關於Libevent的介紹，這裏簡單翻譯介紹一下：
Libevent是以事件為驅動的開發可擴展的網絡服務端的庫。
開放的API設置事件的回調函數，當事件來暫時調用這個回調函數。它還支持信號和定時器。
開發人員僅僅須要簡單的add/remove來將事件加入到event loop中，通過event_dispatch驅動event。
Libevent支持 /dev/poll, kqueue(2), select(2), poll(2),
epoll(4), and evports。
內部的事件機制和應用接口相互獨立，因此內部實現的更新不影響應用程序。
Libevent能夠用於多線程。
安裝
在官網下載http://libevent.org。我下載了最新版本號libevent-2.0.22-stable.tar.gz。放到文件夾，解壓縮tar -zxvf ibevent-2.0.22-stable.tar.gz。
解壓後進入文件夾，進行配置。把庫安裝到/usr文件夾下
./configure --prefix=/usr編譯安裝
sudo make
sudo make install查看是否成功安裝：
ls -al /usr/lib|grep libevent
lrwxrwxrwx 1 樣例
寫各測試程序，編譯時要設置參數-levent，連接libevent的庫。
echoServer.cc
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <stdio.h>
#include <string.h>
#include <event.h>
#include <stdlib.h>
#include <unistd.h>
#define PORT 8000
#define BACKLOG 5
#define MEM_SIZE 1024
struct event_base* base;
struct sockEvent
{
struct event* readEvent;
struct event* writeEvent;
char* buffer;
};
void releaseSockEvent(struct sockEvent* ev)//delete from base and free it
{
event_del(ev->readEvent);
free(ev->readEvent);
free(ev->writeEvent);
free(ev->buffer);
free(ev);
}
void handleWrite(int sock, short event, void* arg)
{
char* buffer = (char*)arg;
send(sock, buffer, strlen(buffer), 0);
free(buffer);
}
void handldRead(int sock, short event, void* arg)
{
struct event* writeEvent;
int size;
struct sockEvent* ev = (struct sockEvent*)arg;
ev->buffer = (char*)malloc(MEM_SIZE);
bzero(ev->buffer, MEM_SIZE);
size = recv(sock, ev->buffer, MEM_SIZE, 0);
printf("receive data:%s, size:%d\n", ev->buffer, size);
if (size == 0) //client has send FIN
{
releaseSockEvent(ev);
close(sock);
return;
}
//add event to base to send the received data
event_set(ev->writeEvent, sock, EV_WRITE, handleWrite, ev->buffer);
event_base_set(base, ev->writeEvent);
event_add(ev->writeEvent, NULL);
}
void handleAccept(int sock, short event, void* arg)//when new connection coming, calling this func
{
struct sockaddr_in cli_addr;
int newfd;
socklen_t sinSize;
struct sockEvent* ev = (struct sockEvent*)malloc(sizeof(struct sockEvent));
ev->readEvent = (struct event*)malloc(sizeof(struct event));
ev->writeEvent = (struct event*)malloc(sizeof(struct event));
sinSize = sizeof(struct sockaddr_in);
newfd = accept(sock, (struct sockaddr*)&cli_addr, &sinSize);
//set the new coming connection event
event_set(ev->readEvent, newfd, EV_READ|EV_PERSIST, handldRead, ev);
event_base_set(base, ev->readEvent);
event_add(ev->readEvent, NULL);
}
int main(int argc, char* argv[])
{
struct sockaddr_in serverAddr;
int sock;
sock = socket(AF_INET, SOCK_STREAM, 0);
int on = 1;
setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(int));
//memset(&serverAddr, 0, sizeof(serverAddr));
bzero(&serverAddr, sizeof(serverAddr));
serverAddr.sin_family = AF_INET;
serverAddr.sin_port = htons(PORT);
serverAddr.sin_addr.s_addr = INADDR_ANY;
bind(sock, (struct sockaddr*)&serverAddr, sizeof(struct sockaddr));
listen(sock, BACKLOG);
struct event listenEvent;
base = event_base_new();//Create new EventBase
event_set(&listenEvent, sock, EV_READ|EV_PERSIST, handleAccept, NULL);//conbine listenEvent and it‘s callback function
event_base_set(base, &listenEvent);
event_add(&listenEvent, NULL);
event_base_dispatch(base);//start base
return 0;
}libevent源碼分析-介紹、安裝、使用