由於最近現網的epoll版本服務器，出現了點詭異的問題，不得已改用libev快速上線，在這裡先記錄下簡單的使用實例。代碼中可能存在部分bug，此代碼並非線上跑的代碼，不過已經五髒俱全，如果有任何疑問，歡迎一起討論。
[cpp]
#include <ev.h>
#include <stdio.h>
#include <netinet/in.h>
#include<stdlib.h>
#include <string.h>
#define PORT 57789
#define BUFFER_SIZE 2048
#define MAX_ALLOWED_CLIENT 10240
struct ev_io *libevlist[MAX_ALLOWED_CLIENT] = {NULL};
void accept_cb(struct ev_loop *loop, struct ev_io *watcher, int revents);
void read_cb(struct ev_loop *loop, struct ev_io *watcher, int revents);
void timer_beat(struct ev_loop *loop, struct ev_timer *watcher, int revents);
int freelibev(struct ev_loop *loop, int fd);
int main()
{
struct ev_loop *loop=ev_default_loop(0);
int sd;
struct sockaddr_in addr;
int addr_len = sizeof(addr);
//創建一個io watcher和一個timer watcher
struct ev_io socket_accept;
struct ev_timer timeout_w;
//創建socket連接
sd = socket(PF_INET, SOCK_STREAM, 0);
if(sd < 0)
{
printf("socket error\n");
return -1;
}
bzero(&addr, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_port = htons(PORT);
addr.sin_addr.s_addr = INADDR_ANY;
//正常bind
if(bind(sd, (struct sockaddr*)&addr, sizeof(addr)) != 0)
{
printf("bind error\n");
return -1;
}
//正常listen
if(listen(sd, SOMAXCONN) < 0)
{
printf("listen error\n");
return -1;
}
//設置fd可重用
int bReuseaddr=1;
if(setsockopt(sd,SOL_SOCKET ,SO_REUSEADDR,(const char*)&bReuseaddr,sizeof(bReuseaddr)) != 0)
{
printf("setsockopt error in reuseaddr[%d]\n", sd);
return ;
}
//初始化io watcher，用於監聽fd
ev_io_init(&socket_accept, accept_cb, sd, EV_READ);
ev_io_start(loop, &socket_accept);
//可以向遠端發送心跳包
//ev_timer_init(&timeout_w, timer_beat, 1., 0.);
//ev_timer_start(loop, &timeout_w);
ev_run(loop, 0);
return 1;
}
void accept_cb(struct ev_loop *loop, struct ev_io *watcher, int revents)
{
/*
如果有鏈接，則繼續監聽fd；
*/
struct sockaddr_in client_addr;
socklen_t client_len = sizeof(client_addr);
int client_sd;
//創建客戶端的io watcher
struct ev_io *w_client = (struct ev_io*) malloc(sizeof(struct ev_io));
if(w_client == NULL)
{
printf("malloc error in accept_cb\n");
return ;
}
if(EV_ERROR & revents)
{
printf("error event in accept\n");
return ;
}
//獲取與客戶端相連的fd
client_sd = accept(watcher->fd, (struct sockaddr*)&client_addr, &client_len);
if(client_sd < 0)
{
printf("accept error\n");
return;
}
//如果連接數超出指定范圍，則關閉連接
if( client_sd > MAX_ALLOWED_CLIENT)
{
printf("fd too large[%d]\n", client_sd);
close(client_sd);
return ;
}
if(libevlist[client_sd] != NULL)
{
printf("client_sd not NULL fd is [%d]\n", client_sd);
return ;
}
printf("client connected\n");
//監聽新的fd
ev_io_init(w_client, read_cb, client_sd, EV_READ);
ev_io_start(loop, w_client);
libevlist[client_sd] = w_client;
}
void read_cb(struct ev_loop *loop, struct ev_io *watcher, int revents)
{
char buffer[BUFFER_SIZE];
ssize_t read;
if(EV_ERROR & revents)
{
printf("error event in read\n");
return ;
}
//正常的recv
read = recv(watcher->fd, buffer, BUFFER_SIZE, 0);
if(read < 0)
{
printf("read error\n");
return;
}
if(read == 0)
{
printf("client disconnected.\n");
//ev_io_stop(loop, watcher);
//free(watcher);
//如果客戶端斷開連接，釋放響應的資源，並且關閉監聽
freelibev(loop, watcher->fd);
return;
}
else
{
//buffer[read] = '\0';
printf("receive message:%s\n", buffer);
}
//返回給客戶端
send(watcher->fd, buffer, read, 0);
bzero(buffer, read);
}
void timer_beat(struct ev_loop *loop, struct ev_timer *watcher, int revents)
{
float timeout = 2.0;
//這裡可以發送心跳包，也可以什麼都不做
printf("send beat per[%f]\n",timeout);
fflush(stdout);
if(EV_ERROR & revents)
{
printf("error event in timer_beat\n");
return ;
}
ev_timer_set(watcher, timeout,0.);
ev_timer_start(loop, watcher);
return;
}
int freelibev(struct ev_loop *loop, int fd)
{
/*if(fd > MAX_ALLOWED_CLIENT)
{
printf("more than MAX_ALLOWED_CLIENT[%d]", fd);
return -1;
}*/
//清理相關資源
if(libevlist[fd] == NULL)
{
printf("the fd already freed[%d]\n", fd);
return -1;
}
close(fd);
ev_io_stop(loop, libevlist[fd]);
free(libevlist[fd]);
libevlist[fd] = NULL;
return 1;
}
makefile：
[cpp]
CC=gcc
FLAGS=-I. -I/home/lengzijian/c/libev/libev-4.11
LDFLAGS=-L/usr/lib -L/home/lengzijian/c/libev/libev-4.11/.libs -lev -Wall
OBJECTS=server.o
ALL_BIN=server
all:$(ALL_BIN)
$(ALL_BIN):$(OBJECTS)
$(CC) $(FLAGS) $(LDFLAGS) -o $@ $^
%.o:%.c
$(CC) -c $< $(FLAGS) $(FLAGS)
clean:
rm -fr $(OBJECTS)
rm -fr $(ALL_BIN)
注意makefile中的頭文件路徑，和動態鏈接庫的路徑
