Need help spawning a child

[Jonathan I. Kamens]

In article <14972 at pasteur.Berkeley.EDU> gar at cory.Berkeley.EDU.UUCP (Gary D.
Wong) writes:

>My problem is, that to prevent a zombie process, I have to ignore
>SIGCLD with sigignore(SIGCLD), and my parent process does not wake
>up.  Is there any other way to prevent a zombie other than by
>ignoring SIGCLD?

I've posted this already; you should read the whole message chain
before asking a question that has already been answered.  Using
sigignore(SIGCLD) to get rid of zombie processes is unportable, and
will only work on SysV-based systems.  The portable way to get rid of
zombie processes is to establish a signal handler for the SIGCLD
signal, and to do wait(0) in that signal handler.  The wait(0) call
cleans up exited child processes and "allows" them to exit.

>Also, does anyone know what will happen to my sleeping process after
>the signal handling call? Will it go back to sleep, or continue as if
>it were given the alarm signal? What would be the effect of having
>the signal handler send the alarm signal to the process?

If a call to sleep() is interrupted by a signal for which a signal
handler has been established, then the sleep() will resume where it
left off after the signal handler exits.  I am fairly sure this will
happen on all architectures; I just tested it on BSD, so I know it
will happen there.

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