Re: Clarification needed on signal spec EXIT

[Francis Moreau]

Chester,

You could you clarify/help, please ?

On Wed, Oct 17, 2012 at 11:13 AM, Francis Moreau <francis.moro@gmail.com> wrote:
> On Tue, Oct 16, 2012 at 10:00 PM, Bob Proulx <bob@proulx.com> wrote:
>> Francis Moreau wrote:
>>> --------------
>>> main_cleanup () { echo main cleanup; }
>>> submain_cleanup () { echo sub cleanup; }
>>>
>>> trap main_cleanup EXIT
>>>
>>> task_in_background () {
>>>         echo "subshell $BASHPID"
>>>
>>>         while :; do
>>>                 # echo "FOO"
>>>                 sleep 1
>>>         done
>>>         echo "subshell exiting..."
>>> }
>>>
>>> {
>>>         trap submain_cleanup EXIT
>>>         trap
>>>         task_in_background
>>> } &
>>>
>>> echo exiting...
>>> --------------
>>>
>>> Sending TERM signal to the subshell doesn't make "submain_cleanup()"
>>> to be called.
>>
>> And it does in ksh93.  Hmm...  And it does if I comment out the line
>> "trap main_cleanup EXIT".  It seems to only set the trap if no trap
>> handler was previously set.
>
> Yes that's right.
>
> Even weirder: if the subshell exits by calling "exit 1", then the trap
> handler is not called at all regardless of whether or not the "trap
> main_cleanup EXIT" is commented you.
>
> To make that case work, you need to use the "( ... ) &" construct
> instead of "{ ... } &" one.
>
> This is why I was asking for clarification :)
> --
> Francis



-- 
Francis