短视频app开发，Timer-定时器

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我是靠谱客的博主仁爱睫毛膏，最近开发中收集的这篇文章主要介绍短视频app开发，Timer-定时器，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

短视频app开发，Timer-定时器实现的相关代码
一、timer_create() + timer_settime()定时器

精确到nsec级.

1.1 main.cpp

#include <stdio.h>
#include <signal.h>
#include <time.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include<sys/time.h>
 
#define TIMER_SIVAL 9006
 
#define TIMER_START_TIME 3
#define TIMER_LOOP_TIME 1
 
struct timeval g_tv;
struct timezone g_tz;
 
void timer_thread(union sigval v)
{
    struct timeval tv;
    struct timezone tz;
    gettimeofday (&tv , &tz);
    printf("[sival:%d]sec:%ld,usec:%ldn",v.sival_int,(tv.tv_sec - g_tv.tv_sec),(tv.tv_usec - g_tv.tv_usec));
 
}
 
int main()
{
 
    timer_t timerid;
    struct sigevent evp;
    memset(&evp, 0, sizeof(struct sigevent));       //清零初始化 
 
    evp.sigev_value.sival_int = TIMER_SIVAL;        //标识定时器的，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(CLOCK_REALTIME, &evp, &timerid) == -1)
    {
        perror("fail to timer_create");
        exit(-1);
    }
 
    //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 = TIMER_LOOP_TIME; //回调函数执行频率为(tv_sec+tv_nsec)运行1次
    it.it_interval.tv_nsec = 0;
    it.it_value.tv_sec = TIMER_START_TIME;   //倒计时(tv_sec+tv_nsec)秒开始调用回调函数
    it.it_value.tv_nsec = 0;
 
    if (timer_settime(timerid, 0, &it, NULL) == -1)
    {
        perror("fail to timer_settime");
        exit(-1);
    }
 
    gettimeofday (&g_tv , &g_tz);
 
    //pause();
    while (1);
 
    return 0;
}

1.2 result

[sival:9006]sec:3,usec:93
[sival:9006]sec:4,usec:76
[sival:9006]sec:5,usec:78
[sival:9006]sec:6,usec:76
[sival:9006]sec:7,usec:79
[sival:9006]sec:8,usec:80
[sival:9006]sec:9,usec:74

二、信号量SIGALRM + alarm()定时器

精确到second级

2.1 main

#include <stdio.h>
#include <unistd.h>
#include <signal.h>
#include<sys/time.h>
 
#define TIMER_START_TIME 3    
#define TIMER_LOOP_TIME 1     
 
struct timeval g_tv_before;
struct timeval g_tv_after;
 
void signal_handle(int sig)
{
    struct timeval tv;
    struct timezone tz;
    gettimeofday (&tv , &tz);
    printf("[sig:%d]sec:%ld,usec:%ldn",sig,(tv.tv_sec - g_tv_before.tv_sec),(tv.tv_usec - g_tv_before.tv_usec));
 
    if(sig == SIGALRM){
       alarm(TIMER_LOOP_TIME);
    }
 
}
 
int main()
{
 
    signal(SIGALRM, signal_handle); //注册安装信号
 
    gettimeofday (&g_tv_before,NULL);
 
    alarm(TIMER_START_TIME);        //触发定时器 //精度能达到1秒,是无法低于1秒的精度
 
    gettimeofday (&g_tv_after,NULL);
    printf("[alarm cost]sec:%ld,usec:%ldn",(g_tv_after.tv_sec - g_tv_before.tv_sec),(g_tv_after.tv_usec - g_tv_before.tv_usec));
 
    //pause();
    while (1);
 
    return 0;
}

2.2 result

[alarm cost]sec:0,usec:12
[sig:14]sec:3,usec:14
[sig:14]sec:4,usec:23
[sig:14]sec:5,usec:33
[sig:14]sec:6,usec:43
[sig:14]sec:7,usec:52

附:

Makefile

##dir
PWD_DIR=$(shell pwd)
OBJ_DIR=$(PWD_DIR)/obj
BIN_DIR=$(PWD_DIR)/bin
 
##compiler
CC=gcc
 
##target
TARGET=timer
 
##build
$(TARGET):main.o
        $(CC) main.o -o $@ -lrt
main.o:main.cpp
        $(CC) -c $^ 
clean:
        rm -rf *.o timer