Hi,
thanks Jack for that, I've already seen this solution on the list,
but I need to know when the pd subprocess ends and with a '&' i get a '0' on [shell] rightmost outlet when 'echo pid $1' command ends and not when pd ends
moreover when killing Pd the external's destroy() method isn't called and this could block some hardware (like cameras...)
but maybe I was not clear enough since I have several questions in one thread...
the problem was to exit all shell subprocess when quitting pd
I solved it thanks to Cyrille by adding a watchdog
the main pd send a "ping" each 100ms to all children, if there is no "ping" during 1 second, the child kill itself
so the main pd can quit safely
king regards
antoine