Let's get started with the flag SA_NOCLDWAIT. First, a quick digression:
As we learned in Chapter 10, Process Creation, a process can fork, resulting in an act of creation: a new child process is born! From that chapter, it is now relevant to recall our Fork Rule #7: The parent process must wait (block) upon the termination (death) of every child, directly or indirectly.
The parent process can wait (block) upon the child's termination via the wait system call API set. As we learned earlier, this is essential: if the child dies and the parent has not waited upon it, the child becomes a zombie—an undesirable state to be in, at best. At worst, it can terribly clog system resources.
However, blocking upon the death of the ...
