Re: sh won't trap SIGHUP while waiting for jobs

["J. Lewis Muir" <jlmuir%imca-cat.org@localhost>]

On 8/20/15 7:50 PM, Travis Paul wrote:
> sleep (/bin/sleep) isn't built-in to /bin/sh, so my guess is that
> /bin/sleep is catching signal. I think that the 2nd version works
> because when you have a loop in sh and sleep for 1 second and there is
> time for /bin/sh to catch the signal.

Hi, Travis.

Thanks for your reply!  For the second version, I think it works because
sh "sees" the signal once the "sleep 1" returns.

For the first version, I still don't understand why sh doesn't "see"
the signal while waiting in the wait.  That's the behavior that seems
strange to me.  As far as your guess that /bin/sleep is catching the
signal, I don't understand that.  When I run "/bin/sleep 3600" on its
own in a terminal and send it SIGHUP, it exits immediately like this:

=== sleep terminal ===
$ /bin/sleep 3600
Hangup
======================

So, if, when running in test-program, it is catching the SIGHUP that
was sent to test-program, why wouldn't it just exit like it does when I
send the SIGHUP to it directly, and then test-program should exit since
the wait should return?  Furthermore, since the sleep is running in the
background, I don't understand how a SIGHUP sent to test-program would
somehow get caught by the sleep; that doesn't make sense to me.

Thanks!

Lewis