【Linux学习】倒计时退出,当进程收到SIGUSR1信号时开始倒计时，3秒钟后退出程序。

题目3：

编写一个程序实现倒计时退出功能，当进程收到SIGUSR1信号时开始倒计时，3秒钟后退出程序。
要求在终端上输出收到信号并开始倒计时的过程
如：
The process is terminating in 3 sec...
The process is terminating in 2 sec...
The process is terminating in 1 sec...

 1 #include <sys/types.h>
 2 #include <unistd.h>
 3 #include <signal.h>
 4 #include <stdlib.h>
 5 #include <string.h>
 6 #include <stdio.h>
 7 #include <errno.h>
 8 #include <signal.h>
 9
10 int g_tag;
11
12 void  myhandle(int num)
13 {
14     printf("recv signal id num : %d \n", num);
15     if (num == 10)
16     {
17         g_tag = 0;
18     }
19 }
20
21 int main(void)
22 {
23
24     g_tag = 1;
25
26
27     if ( signal(SIGUSR1, myhandle) == SIG_ERR )
28     {
29         perror("signal err");
30         return 0;
31     }
32
33     while(1)
34     {
35         if(g_tag == 0)
36         {
37             printf("The process is terminating in 3 sec...\n");
38             sleep(1);
39             printf("The process is terminating in 2 sec...\n");
40             sleep(1);
41             printf("The process is terminating in 1 sec...\n");
42             sleep(1);
43             break;
44         }
45     }
46
47
48     return 0;
49 }