C语言实现多线程定时器实例讲解

void settick(int val);

void addtimertask(timertask task, int val, int autoreset, void *arg);

task_start(test2, arg)

	//body
 arg *temp = (arg*)arg;
 temp->ret = temp->a + temp->b;
 printf("this is a test2\n");

task_end

void timerwait();

void timerstop();

void starttimer();

#include <stdio.h>
#include "timer.h"

typedef struct argument{
 int a;
 int b;
 int ret;
}arg;

//任务1，打印语句
task_start(test1, arg)
 printf("this is a test1\n");
task_end

//任务2，计算arg中两个数的和，打印语句
task_start(test2, arg)

 arg *temp = (arg*)arg;
 temp->ret = temp->a + temp->b;
 printf("this is a test2\n");

task_end

//任务3，打印语句
task_start(test3, arg)
 printf("this is a test3\n");
task_end

void main(){

 arg arg;

	//设置tick 为 500ms
 settick(500 * 1000);

	//添加任务1到任务列表，设置定时器时间为2.5s，重复执行，无参数
 addtimertask(test1, 5, autoreset, null);
 arg.a = 2; arg.b = 3;
 //添加任务2到任务列表，设置定时器时间为0.5s，不重复执行，参数为arg
 addtimertask(test2, 1, noreset, &arg);
 //添加任务3到任务列表，设置定时器时间为1s，重复执行，无参数
 addtimertask(test3, 2, autoreset, null);

	//启动定时器
 starttimer();
 printf("timer is started\n");
 //程序等待5秒
 sleep(5);
 //停止定时器
 timerstop();
 //等待所有任务执行完毕
 timerwait();
 //打印任务二的计算结果
 printf("%d\n", arg.ret);

}

#ifndef timer_h
#define timer_h
#include <unistd.h>
#include <stdio.h>
#include <pthread.h>
#include <stdlib.h>
#include <signal.h>
#define autoreset 1
#define noreset 0
#define task_start(name, arg) void* name(void *arg){
#define task_end return null;} 
typedef void* (*timertask)(void* arg);
struct taskitem{
 timertask task;
 int init_counter;
 int counter;
 pthread_t th;
 void *arg;
 void *ret;
 int flag;
 int autoreset;
 struct taskitem *next;
 
};
void settick(int val);
void* eventloop(void* arg);
void addtimertask(timertask task, int val, int autoreset, void *arg);
void timerwait();
void timerstop();
void starttimer();
#endif //timer_h

#include "timer.h"
#define stopflag 0
#define runflag 1 
static int tick = 1000 * 1000;
static struct taskitem head = {
 .next = null,
};
static pthread_t loop_thread;
static int flag = stopflag;
static int tasknum = 0;

void settick(int val){
 tick = val;
}
void* eventloop(void* arg){
 
 struct taskitem *task = head.next;
 struct taskitem *pretask = &head;

 while(flag == runflag && tasknum > 0){
  
  while(task != null){
   if(task->counter == 0){ // it is time for doing task
    if(task->flag == stopflag){ // task is not created
     if(0 != pthread_create(&(task->th), null, task->task, task->arg)){ // do a task
      printf("failed to create user's task");
     }
     else{
      task->flag = runflag;
     }
    }
    else{
     if(0 != pthread_kill(task->th, 0)){ // current task is completed
      if(task->autoreset == autoreset){ // repeat execute
       task->counter = task->init_counter;
       task->flag = stopflag;
      }
      else{ // delete a task
       pretask->next = task->next;
       free(task);
       task = pretask->next;
       tasknum--;
       continue;
      }
     }
    }
   }
   else{
    task->counter--;
   }
   pretask = pretask->next;
   task = task->next;
  }
  usleep(tick); // sleep a tick
  task = head.next;
  pretask = &head;
 }
 flag = stopflag;
}
void addtimertask(timertask task, int val, int autoreset, void *arg){
 struct taskitem *node;
 node = (struct taskitem*)malloc(sizeof(struct taskitem));
 node->next = head.next;
 head.next = node;
 node->arg = arg;
 node->counter = val;
 node->init_counter = val;
 node->task = task;
 node->flag = stopflag;
 node->autoreset = autoreset;
 tasknum++;
}
void timerwait(){
 pthread_join(loop_thread, null);
}
void timerstop(){
 flag = stopflag;
}
void starttimer(){
 flag = runflag;
 if(0 != pthread_create(&loop_thread, null, eventloop, null)){
  printf("failed to create loop task.\n");
 }
}