进程可以等待不是子进程之一的 PID 吗？
Can a process wait for a PID that is not one of the children?
我想知道我们是否可以使用系统调用
waitpid()
等待孙子的 pid
waitpid() 是 POSIX。
The wait() and waitpid() functions shall obtain status information (see Status Information) pertaining to one of the caller's child processes.
所以你的问题的答案是 "No"，至少从标准的角度来看是这样。
这不一定要阻止实现提供对标准的扩展。
来自 POSIX 还有：
Nothing in this volume of POSIX.1-2008 prevents an implementation from providing extensions that permit a process to get status from a grandchild or any other process, but a process that does not use such extensions must be guaranteed to see status from only its direct children.
我想知道我们是否可以使用系统调用
waitpid()
等待孙子的 pid
waitpid() 是 POSIX。
The wait() and waitpid() functions shall obtain status information (see Status Information) pertaining to one of the caller's child processes.
所以你的问题的答案是 "No"，至少从标准的角度来看是这样。
这不一定要阻止实现提供对标准的扩展。
来自 POSIX 还有：
Nothing in this volume of POSIX.1-2008 prevents an implementation from providing extensions that permit a process to get status from a grandchild or any other process, but a process that does not use such extensions must be guaranteed to see status from only its direct children.