关于C#：fork()和父/子进程ID

fork() and parent/child process ids

对于以下两个程序中的子进程为什么显示不同的父代id，我有些困惑。

第一个程序：

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int main ( void ) {
int pid, fpid, ppid;
fpid = fork ();
pid = getpid();
ppid = getppid();
printf ("fpid is %d\
", fpid);
sleep(5);
if (fpid > 0){
printf ("\
This is Parent. My pid %d. My parent's pid %d\
",pid,ppid);
}
else if (fpid ==0){
sleep(1);
printf ("\
This is Child. My pid %d. My parent's pid %d\
",pid,ppid);
}
else
printf ("fork failed\
");
return (0);
}

输出：

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fpid is 53560
fpid is 0

This is Parent. My pid 53559. My parent's pid 44632

MacBook-Pro:~/Desktop/$

This is Child. My pid 53560. My parent's pid 53559

第二个程序：

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int main ( void ) {
int pid, fpid, ppid;
fpid = fork ();
printf ("fpid is is %d\
", fpid);
sleep(5);
if (fpid > 0){
pid = getpid();
ppid = getppid();
printf ("\
This is Parent. My pid %d. My parent's pid %d\
",pid,ppid);
}
else if (fpid ==0){
sleep(1);
pid = getpid();
ppid = getppid();
printf ("\
This is Child. My pid %d. My parent's pid %d\
",pid,ppid);
}
else
printf ("fork failed\
");
return (0);
}

输出：

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fpid is is 53635
fpid is is 0

This is Parent. My pid 53634. My parent's pid 44632

MacBook-Pro:~/Desktop$

This is Child. My pid 53635. My parent's pid 1

我了解到进程1是原始父级终止后接任父级的进程。我想我想知道的是：在这两种情况下，子进程都不能先完成父进程，然后子进程才能处理其printf吗？输出不应该相同吗？