好的，所以我一直在努力学习掌握子进程并正确等待它们完成。我已经阅读了很多 Stack Overflow Q/A，但我似乎仍然无法按照我的意愿让它工作。我一直在阅读/搜索这本书（C++ Primer plus 6th ed.）——我已经做了一些研究，但我仍然不能让它像我想要的那样等待。
因此，我在 Stack Overflow 上查看了几件事以供参考：Checking the status of a child process in C++
这是我到目前为止所尝试的：
using namespace std;
int main() {
int status;
pid_t child;
child = fork();
if ( child > 0 ) {
cout << "\nChild #1 is in charge\n";
execlp("ls", "ls", NULL);
}
else if ( child < 0 ) {
cout << "\nSomething wen't wrong in the forking process\n";
}
else {
}
child = fork();
if ( child > 0 ) {
cout << "\nSecond child is in charge\n";
execlp("locate", "locate", "etc", NULL);
}
else if ( child < 0 ) {
cout << "\nSomething went wrong in the forking of second child!\n";
}
else {
}
现在这将显示Child #1 is in charge，Second child is in charge然后它将混合两个命令（我ls在 locate 之间看到一些etc）。
我尝试过的第二件事：
using namespace std;
int main() {
int status;
pid_t child;
pid_t ch_status = waitpid(child, &status, WNOHANG);
child = fork();
if ( child > 0 ) {
cout << "\nChild is in charge\n";
execlp("ls", "ls", NULL);
}
else if ( child < 0 ) {
cout << "\nSomething wen't wrong in the forking process\n";
}
if ( ch_status == 0 ) {
}
else if ( ch_status == -1 ) {
cout << "\nERROR IN CHILD #1\n";
}
else {
}
child = fork();
if ( child == 0 ) {
cout << "\nSecond child is in charge\n";
execlp("locate", "locate", "etc", NULL);
}
else if ( child < 0 ) {
cout << "\nSomething went wrong in the forking of second child!\n";
}
if ( ch_status == 0 ) {
}
else if ( ch_status == -1 ) {
cout << "\nERROR IN CHILD #1\n";
}
else {
}
child = fork();
if ( child > 0 ) {
cout << "\nThird child is in charge!\n";
execlp("echo", "echo", "herro", NULL);
}
else if ( child < 0 ) {
cout << "\nForking of third child failed!\n";
}
if ( ch_status == 0 ) {
}
else if ( ch_status == -1 ) {
cout << "\nERROR IN CHILD #2\n";
}
else {
}
return 0;
}
这更多地基于我提供的链接，它产生了与我第一次测试运行相同的结果，除了它还会显示ERROR IN CHILD #1/2.
这些命令是无关紧要的，我只是想不明白我在这里做错了什么......我也尝试过将它们嵌套在 中else { //start second fork here }，但我也无济于事。
根据我阅读waitpid(2)我应该使用的手册后的理解WNOHANG；
http://linux.die.net/man/2/waitpid
非常感谢任何建议/指针。
如果可能，请提交您将如何完成正确结果的示例代码(execute command 1 -> wait until done -> execute command 2 -> exit)。
期待回复。