I think others have explained this. Basically when the child exits, the OS keeps track of it's exit status until you check it. This is done so that you can find out what happened to it..did it work ok? Was there an error that caused it to abend? If you don't check and clear the status of the child termination, then this status hangs around forever in zombie land. It doesn't consume CPU mips, but it does occupy a place in the process table.

In reply to Re^3: Check if forked process is dead by Marshall
in thread Check if forked process is dead by petr999

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