> After much study I have a new theory. It appears that the
> pipe machinery
> is working fine, but that sometimes my program fails to
> "reap" all of its
> terminated child processes. I'm using a `sigCHLD` signal handler that
> does `getAnyProcessStatus True False` each time it's invoked.
> It seems
> that one or more `sigCHLD` signals are occurring while an
> instance of the
> handler is already running (having presumably blocked
> `sigCHLD` during its
> execution), and hence the "contemporaneous" signals are getting lost.
> (Oh, and it seems this unfortunate behavior occurs for me
> under Linux but
> not Solaris.)
>
> How can I avoid losing `sigCHLD` signals?
>
> It seems that use of the `SA_NODEFER` flag on `sigaction` might do the
> trick, but that flag is not accessible via `installHandler`.
I can't see a reason why SIGCHLD signals might be lost, but the handler
might be deferred in the way that Volker described if you have blocking
C calls.
Perhaps you could investigate with strace and see if the signal is
actually being delivered?
Cheers,
Simon
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