子进程在分叉和执行后变得失效

我正在学习fork和exec，并使用fork和execlp创建多个子进程，我在子进程中所做的只是让它睡觉。基本上，我只想让我所有的孩子都活着。但是一旦我启动我的监视器.cpp它创建的进程，所有孩子都会立即退出，他们确实不复存在！

监视哪个分支多个子项

#include <iostream>
#include <thread>
#include <chrono>
#include <string>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
int main(int argc, char* argv[])
{
for(size_t i=0; i<std::stoi(argv[1]) ; ++i)
{
int pid = fork();
if(pid == 0)
{
execlp("child", "child", std::string(std::to_string(i)).c_str(), (char *)0);
std::cout << "child exiting " << std::endl;
exit(1);
}
else if(pid > 0)
{
std::cout <<"child started with " << pid << std::endl;
}
else
{
std::cout << "fork failed" << std::endl;
}
}
while(true)
{
std::this_thread::sleep_for(std::chrono::seconds(100000));
}
return 0;
}

儿童代码

#include <iostream>
#include <thread>
#include <chrono>
int main(int argc, char* argv[])
{
std::cout << " child started with id " << argv[1] << std::endl;
std::cout <<"child sleeping " << argv[1] << std::endl;
std::this_thread::sleep_for(std::chrono::seconds(1000));
std::cout << "child exiting " << argv[1] << std::endl;
return 0;
}

输出：

child started with 1834
child started with 1835
child exiting 
child started with 1836
child exiting 
child started with 1837
child started with 1838
child started with 1839
child exiting 
child started with 1840
child started with 1841
child exiting 
child started with 1842
child started with 1843
child exiting 
child exiting 
child exiting 
child exiting 
child exiting 
child exiting

ps -ef 将我的所有子进程显示为已停用，即使我的父进程还活着。

你能解释一下我错过了什么吗？