libevent库简单使用

创建一个事件处理框架并显示系统中可以用那些io转接函数，以及现在使用的是哪种，并消除该事件

#include <iostream>
#include <event2/event.h>using namespace std;int main()
{struct event_base* base = NULL;base = event_base_new();//创建新的事件框架const char** meths = event_get_supported_methods();//显示系统中可以使用哪些io转接函数for (int i=0; meths[i] != NULL; ++i){cout<<meths[i];}cout<<"\ncurrent = "<<event_base_get_method(base);//显示当前使用的是哪一种转接函数event_base_free(base);//释放事件框架return 0;
}

用libevent库写有名管道通信

读端程序

#include <iostream>
#include <event2/event.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>using namespace std;void cb(evutil_socket_t fd, short what, void * arg)
{char buf[256];int n=read(fd, buf, sizeof(buf));if (n==-1){cout<<"read is error!\n";exit(1);}cout<<"the buf is "<<buf<<endl;
}int main()
{unlink("myfifo");mkfifo("myfifo", 0664);int fd=open("myfifo", O_RDONLY | O_NONBLOCK);struct event_base* base=NULL;base=event_base_new();struct event *ev=NULL;ev=event_new(base, fd, EV_READ | EV_PERSIST, cb, NULL);event_add(ev, NULL);event_base_dispatch(base);event_free(ev);event_base_free(base);close(fd);
}

写端程序

#include <iostream>
#include <event2/event.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h> 
#include <string.h>using namespace std;void cb(evutil_socket_t fd, short what, void * arg)
{char buf[256]="hello world";static int num=0;sleep(1);//printf(buf, "hello world! %d\n", ++num);cout<<buf<<endl;write(fd, buf, strlen(buf));
}int main()
{int fd=open("myfifo", O_WRONLY | O_NONBLOCK);struct event_base* base=NULL;base=event_base_new();struct event *ev=NULL;ev=event_new(base, fd, EV_WRITE | EV_PERSIST, cb, NULL);event_add(ev, NULL);event_base_dispatch(base);event_free(ev);event_base_free(base);close(fd);
}