C 父进程不使用signal（）等待所有子进程退出

程序最初要求用户输入要创建的子进程数。创建子对象后，父对象睡眠并等待其所有子对象通过向SIGCHLD注册的信号处理程序函数“handle_child”终止

#include <stdio.h>
#include <stdlib.h>
#include <signal.h>

int to_kill;

void handle_child(int sig)
{
    pid_t id = wait(NULL);
    printf("Reaped child with PID = %d\n",id);
    --to_kill;
    if(to_kill == 0){
        printf("~All children have been reaped successfully.. parent will now exit~\n");
        exit(0);
    }
}

int main()
{
    pid_t id, parent_id = getpid();
    int children, i;
    signal(SIGCHLD, handle_child);
    printf("Enter number of child processes to spawn: ");
    scanf("%d",&children);
    to_kill = children;
    for(i = 0; i < children; ++i){
        id = fork();
        if(id == 0){
            printf("New child with pid = %d\n",getpid());
            sleep(2);
            return 0;
        }
        sleep(1);
    }
    sleep(30);
    return 0;
}

我认为对睡眠的调用（30）被SIGCHLD中断中断，因此它在30秒内不会睡眠，而是在调用信号处理程序后立即返回

要想正确，您需要在循环中睡觉：

tosleep = 30;
while (tosleep > 0) {
    tosleep = sleep(tosleep);
}

---

谢谢，这解决了问题！不知道sleep（）因信号而中断。。

tosleep = 30;
while (tosleep > 0) {
    tosleep = sleep(tosleep);
}