A libevent helloworld using changelist

helloworld.c

#include <event2/event.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#define BUF_SIZE 1024

void onError(const char *reason)
{
    perror(reason);
    exit(EXIT_FAILURE);
}

void read_cb(int fd,short events,void* arg)
{
    char buf[BUF_SIZE] = {0};
    int ret = read(fd,buf,sizeof(buf)-1);
    if(ret < 0 )
        onError("read()");
    buf[ret] = 0;
    printf("What you type is : %s \n",buf);
}

int main()
{
    struct event_config *cfg = event_config_new();
    
    event_config_set_flag(cfg,EVENT_BASE_FLAG_EPOLL_USE_CHANGELIST);
    struct event_base* base = event_base_new_with_config(cfg);
    if(!base)
        onError("event_base_new()");
    struct event* ev = event_new(base,STDIN_FILENO,EV_READ | EV_PERSIST ,read_cb,NULL);
    if(!ev)
        onError("event_new()");

    event_add(ev,NULL);
    event_base_dispatch(base);

    event_free(ev);
    event_base_free(base);
}