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From: andrew@resam.dk (Leif Andrew Rump)
Newsgroups: comp.windows.x
Subject: Re: Xview: Interrupting a Notify Procedure
Message-ID: <1991Apr29.091327.20052@resam.dk>
Date: 29 Apr 91 09:13:27 GMT
References: <3098@sparko.gwu.edu> <1991Apr24.211819.26355@aifh.ed.ac.uk>
Organization: RESAM Project Office, SAS, CPHML-V
Lines: 60

In <1991Apr24.211819.26355@aifh.ed.ac.uk> gordonc@aifh.ed.ac.uk (Gordon Cameron (RA DAI)) writes:
>From article <3098@sparko.gwu.edu>, by darken@seas.gwu.edu:
>> Here's the problem:
>> Say I have a panel with 2 buttons on it. When I hit
>> button #1, I want to start a process which will continue
>> until button #2 is hit. How can I interrupt the notify
>> procedure of button #1 when #2 is hit? As I see it,
>> the pressing of #2 will not be recognized until #1
>> is completed processing. I looked into events in
>> addition to notifications but nothing works yet and
>> the manual is rather shady in this area. Thanks in
>> advance!
>> 

>You could try something like this :
LOTS OF GOOD CODE DELETED

>What this does is to run the routine 'do_something' when you press
>the button #1. How ?? Pressing the button triggers the callback
>which sets a global variable, and calls notify_stop.
>The notifier returns to the top level, and then notify_start
>and xv_main_loop return.

>Periodically in this routine, you should make calls to 
>notify_dispatch(), which will make a single pass through the
>notify cycle. If you have pressed button #2, then all you will
>have done is to set the variable finished to TRUE. This is
>detected, and 'do_something' returns so you end up at point (2).
>You can now do whatever you want before continuing with the
>application (perhaps doing some graphical output).

>xv_main_loop then gets called again, and so you are back to where
>you started. I've set a variable running, which when you unset
>and do xv_destroy(Frame) will have the effect of quitting the
>application.
>(To be complete you should write a notify_interspose_destroy_func
>which sets the variable running to FALSE, so the window quit works)


>Hope this is useful - If you're interested, get the O'Reilly book
>'XView Programming Manual' by Dan Heller, as its excellent.
>(see pp 397-400)

Well now we are back to good old MicroSoft Window code! Shouldn't
the window manager be able to handle this by itself, like when
the user envokes notify_dispatch()?

Andrew


Leif Andrew Rump, AmbraSoft A/S, Stroedamvej 50, DK-2100 Copenhagen OE, Denmark
UUCP: andrew@ambra.dk, phone: +45 39 27 11 77                /
Currently at Scandinavian Airline Systems                =======/
UUCP: andrew@resam.dk, phone: +45 32 32 51 54                \
SAS, RESAM Project Office, CPHML-V, P.O.BOX 150, DK-2770 Kastrup, Denmark

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