【linux】select实现定时器

/*秒级定时器*/
void seconds_sleep(unsigned     long  seconds)
{if(seconds == 0) return;struct timeval tv;tv.tv_sec=seconds;tv.tv_usec=0;int err;do{err=select(0,NULL,NULL,NULL,&tv);}while(err<0 && errno==EINTR);
}/*毫秒定时器*/void milliseconds_sleep(unsigned long mSec)
{if(mSec == 0) return;struct timeval tv;tv.tv_sec=mSec/1000;tv.tv_usec=(mSec%1000)*1000;int err;do{err=select(0,NULL,NULL,NULL,&tv);}while(err<0 && errno==EINTR);
}/*微秒定时器*/void microseconds_sleep(unsigned long uSec)
{if(uSec == 0) return;struct timeval tv;tv.tv_sec=uSec/1000000;tv.tv_usec=uSec%1000000;int err;do{err=select(0,NULL,NULL,NULL,&tv);}while(err<0 && errno==EINTR);
}int main()
{int i;for(i=0;i<5;++i){printf("%d\n",i);//seconds_sleep(2);//milliseconds_sleep(2000);microseconds_sleep(2000000);}
}

http://gityuan.com/2019/01/05/linux-poll-select/
https://blog.csdn.net/sjp11/article/details/126312199
https://www.cnblogs.com/sctb/p/17400454.html
https://blog.csdn.net/weixin_37926485/article/details/122810971