linux下定时器的使用--timer_create等系列

时间:2022-10-03 23:30:32

程序1:采用新线程派驻的通知方式

#include <stdio.h>
#include <signal.h>
#include <time.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>

#define CLOCKID CLOCK_REALTIME

void timer_thread(union sigval v)
{
printf("timer_thread function! %d\n", v.sival_int);
}

int main()
{
// XXX int timer_create(clockid_t clockid, struct sigevent *evp, timer_t *timerid);
// clockid--值:CLOCK_REALTIME,CLOCK_MONOTONIC,CLOCK_PROCESS_CPUTIME_ID,CLOCK_THREAD_CPUTIME_ID
// evp--存放环境值的地址,结构成员说明了定时器到期的通知方式和处理方式等
// timerid--定时器标识符
timer_t timerid;
struct sigevent evp;
memset(&evp, 0, sizeof(struct sigevent));//清零初始化

evp.sigev_value.sival_int = 111;//也是标识定时器的,这和timerid有什么区别?回调函数可以获得
evp.sigev_notify = SIGEV_THREAD;//线程通知的方式,派驻新线程
evp.sigev_notify_function = timer_thread;//线程函数地址

if (timer_create(CLOCKID, &evp, &timerid) == -1)
{
perror("fail to timer_create");
exit(-1);
}

// XXX int timer_settime(timer_t timerid, int flags, const struct itimerspec *new_value,struct itimerspec *old_value);
// timerid--定时器标识
// flags--0表示相对时间,1表示绝对时间
// new_value--定时器的新初始值和间隔,如下面的it
// old_value--取值通常为0,即第四个参数常为NULL,若不为NULL,则返回定时器的前一个值

//第一次间隔it.it_value这么长,以后每次都是it.it_interval这么长,就是说it.it_value变0的时候会装载it.it_interval的值
struct itimerspec it;
it.it_interval.tv_sec = 1;
it.it_interval.tv_nsec = 0;
it.it_value.tv_sec = 1;
it.it_value.tv_nsec = 0;

if (timer_settime(timerid, 0, &it, NULL) == -1)
{
perror("fail to timer_settime");
exit(-1);
}

pause();

return 0;
}
/*
* int timer_gettime(timer_t timerid, struct itimerspec *curr_value);
* 获取timerid指定的定时器的值,填入curr_value
*
*/