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SIG_CLD - the missing link

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Rob Oliver

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Apr 8, 1994, 1:38:25 PM4/8/94

To summarize the responses I've received so far...

I have two options:

1) write my own signal handler for SIG_CLD and specify this
as the argument for the signal(SIG_CLD, ---) system call

2) grab the default setting for SIG_CLD from the initial signal call
action=signal(SIG_CLD, SIG_IGN)
as it returns the previous setting and use *this* as an argument
to reset the handler with
signal(SIG_CLD,action)

But I'm still confused...

My personal feeling is this: I prefer to use wait() as my "signal
handler" rather than reproducing it as my own signal handler.
So I prefer option two.

But I am surprised that the signal() system call has no
documented argument to send it for SIG_CLD that will allow
SIG_CLD to be wait()-ed for.

Another way of putting this is, if signal() takes a SIG_DFL argument
to "reset" the signal handler to the *default* action for any
given signal --> why does it not return the handler for SIG_CLD
to its initial state (which IS: when a child process dies the
kernel saves the exit status of the child and stays that way until
the parent calls wait() ). Instead SIG_DFL sets the handler to SIG_IGN,
and the kernel discards the exit status.

Doesn't this seem a bit bizarre?

Thanks for all the responses.

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