利用信號知識褪子，實現(xiàn)多次任意時間調(diào)用函數(shù)

my_alarm.h文件

#ifndef __MY_ALARM_H
#define __MY_ALARM_H 

//最多創(chuàng)建1024個任務
#define MAX 1024

//函數(shù)定義
typedef void alarm_func_t(void*);

//添加任務排嫌，成功返回任務ID，失敗返回-1
int anytimer_alarm(int sec, alarm_func_t *func, void *ch);

//取消任務 成功返回0，失敗返回-1;
int anytimer_destory(int id);

#endif

my_alarm.c文件

#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>
#include <unistd.h>
#include <signal.h>

#include "my_alarm.h"

static void mouder_load(void);        //模塊掛載贸营，設置時間贾漏，信號等
static void handler(int s);           //信號行為
static void mouder_unload(void);      //模塊卸載，恢復時間具伍，信號
static int get_pos(void);             //找空閑位置

//定義任務結(jié)構(gòu)體
struct func_st
{
    int sec;                      //秒數(shù)
    alarm_func_t *func;           //用戶自定義函數(shù)
    void *ch;                     //函數(shù)參數(shù)
};

static struct func_st *line[MAX];      //定義1024長度的數(shù)組存儲結(jié)構(gòu)體地址
static int inited = 0;                 //設置計時器翅雏，只有當inited為0的時候才調(diào)用模塊掛載函數(shù)
struct sigaction oldact;               //舊的信號行為
struct itimerval olditv;               //舊的時間鬧鐘


//添加任務，成功返回任務ID人芽，失敗返回-1
int anytimer_alarm(int sec, alarm_func_t *func, void *ch)
{
    struct func_st *new;
    int pos;

    if(inited == 0)
    {
        mouder_load();
        inited = 1;
    }

    //找空位
    pos = get_pos();
    if(pos < 0)
        return -1;

    new=malloc(sizeof(*new));
    if(new == NULL)
        return -1;

    new -> sec = sec;
    new -> func = func;
    new -> ch = ch;

    line[pos] = new;

    return pos;
}



//取消任務 成功返回0望几，失敗返回-1;
int anytimer_destory(int id)
{
    free(line[id]);
    line[id] = NULL;
}



static void mouder_load(void)
{
    struct sigaction act;
    struct itimerval itv;

    act.sa_handler = handler;
    act.sa_flags = 0;
    sigemptyset(&act.sa_mask);
    sigaction(SIGALRM, &act, &oldact);

    itv.it_interval.tv_sec = 1;
    itv.it_interval.tv_usec = 0;
    itv.it_value.tv_sec = 1;
    itv.it_value.tv_usec = 0;
    setitimer(ITIMER_REAL, &itv, &olditv);

    atexit(mouder_unload);     //鉤子函數(shù)
}


static void handler(int s)
{
    int i;
    for(i=0; i<MAX; i++)
    {
        if (line[i] != NULL)    //找不為空的數(shù)組
        {
            if(line[i] -> sec != 0)                  //當結(jié)構(gòu)體的時間不等于0時，時間減少1
                line[i] -> sec -= 1;       
            else                                    //時間為0執(zhí)行用戶自定義函數(shù)萤厅，并銷毀該任務橄抹，由于對外提供銷毀函數(shù)，所以可以由用戶調(diào)用銷毀惕味，類似父進程為子進程收尸函數(shù)wait()楼誓；
            {
                line[i] -> func(line[i]->ch);     
                anytimer_destory(i); 
            }
        }
    }
}

static int get_pos(void)
{
    for(int i=0; i<MAX; i++)
    {
        if(line[i] == NULL)
            return i;
    }
    return -1;
}

static void mouder_unload(void)
{
    sigaction(SIGALRM, &oldact, NULL);
    setitimer(ITIMER_REAL, &olditv, NULL);
}

調(diào)試文件alrm_hw.c

#include <stdio.h>
#include <unistd.h>

#include "my_alarm.h"

static void any1(void *s)
{
    printf("%s", (char *)s);
    fflush(NULL);
}

static void any2(void *s)
{
    printf("%s", (char *)s);
    fflush(NULL);
}

static void any3(void *s)
{
    printf("%s", (char *)s);
    fflush(NULL);
}

int main(void)
{
    anytimer_alarm(3, any1, "hello");
    anytimer_alarm(2, any2, "world");
    anytimer_alarm(5, any3, "apue");

    /*
     **world*hello**apue******
     */
    while (1) {
        write(1, "*", 1);
        sleep(1);
    }

    return 0;
}

makefile文件

SRC = alrm_hw.o my_alarm.o
OBJ = myalarm 

$(OBJ):$(SRC)
    gcc -o $@ $^

clean:
    rm *.o $(OBJ)

運行結(jié)果

程序運行結(jié)果