Re: Clarification needed on signal spec EXIT

[Chet Ramey]

On 10/16/12 4:00 PM, Bob Proulx 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, this is a bug in bash-4.2.  The subshell doesn't properly reinitialize
the traps if a trap has already been set in the parent.  This was fixed in
late July and will be in the next version of bash.

Chet
-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU    chet@case.edu    http://cnswww.cns.cwru.edu/~chet/