POSIX timer

偏执的太偏执、 2022-02-02 14:07 179阅读 0赞

[https://www.cnblogs.com/LubinLew/p/POSIX-Timer.html][https_www.cnblogs.com_LubinLew_p_POSIX-Timer.html]

## 例子2:循环timer,使用绝对时间 ##

#include <signal.h>    /* union sigval / struct sigevent */
    #include <stdio.h>    /* printf */
    #include <string.h>    /* memset */
    #include <unistd.h> /* sleep */
    #include <time.h>
    
    #define printf_with_time(format, ...)                                        \
    {                                                                            \
        struct timespec spec;                                                    \
        clock_gettime(CLOCK_MONOTONIC, &spec);                                    \
        printf("[%lu:%lu]"format"\n", spec.tv_sec, spec.tv_nsec, ##__VA_ARGS__);\
    }
    
    
    void timer_notify_cb(union sigval val)
    {
        printf_with_time("timer expiration");
    
    }
    
    int main(void)
    {
        /* Variable Definition */
        timer_t id;
        struct timespec spec;
        struct sigevent ent;
        struct itimerspec value;
        struct itimerspec get_val;
    
        /* Init */
        memset(&ent, 0x00, sizeof(struct sigevent));
        memset(&get_val, 0x00, sizeof(struct itimerspec));
        
        /* create a timer */
        ent.sigev_notify = SIGEV_THREAD;
        ent.sigev_notify_function = timer_notify_cb;
        printf_with_time("create timer");
        timer_create(CLOCK_REALTIME, &ent, &id);        /* CLOCK_REALTIME */
    
        /* start a timer */
        clock_gettime(CLOCK_REALTIME, &spec);            /* CLOCK_REALTIME */
        value.it_value.tv_sec = spec.tv_sec + 2;
        value.it_value.tv_nsec = spec.tv_nsec + 0;
        value.it_interval.tv_sec = 1;    /* per second */
        value.it_interval.tv_nsec = 0;
        printf_with_time("start timer");
        timer_settime(id, TIMER_ABSTIME, &value, NULL); /* TIMER_ABSTIME */
    
        sleep(10);
        printf_with_time("delete timer");
        timer_delete(id);
        return 0;
    }

[https_www.cnblogs.com_LubinLew_p_POSIX-Timer.html]: https://www.cnblogs.com/LubinLew/p/POSIX-Timer.html