Re: XForms: signal callback blocked by shortcut

From: Steve Lamont (
Date: Thu Nov 23 2000 - 18:02:59 EST

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    # To subscribers of the xforms list from Steve Lamont <> :

    > > > on my application i'm using fl_add_signal_callback() to register a
    > > > 50Hz timer callback which should be able changing the gui. Doing gui
    > > > interaction works all fine without larger delays calling the callback
    > > > exept when shortcuts are used. The signal delivery seems to be suppended
    > > > from pressing the key to releasing it.
    > >
    > > Can you provide example code which exhibits this behavior? It will
    > > make it considerably easier to find a solution.
    > >
    > I can. ;) You'll find a little program, setting up the usual "Push Me"
    > button, which can be pushed using <space>, ^p and ^m. In addition the
    > signal SIGALRM is generated with 1Hz using setitimer() and catched using
    > fl_set_signal_callback(). The callback does only count a number and prints
    > it. If the Button is pressed using one of the shortcuts, the counting
    > stops - the mentioned blocking, I guess.

    I'm not sure there is a way of fixing this without breaking XForms or
    simply not using the signal callback mechanism. The control flow
    changes whenever a shortcut is invoked and short of mucking with
    XForms internals, there's not much of a way to override this behavior.

    Perhaps TC can make some recommendations when he returns from

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