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Re: large info structure? [message #56181 is a reply to message #56107]

Thu, 04 October 2007 15:40

JD Smith
Messages: 850
Registered: December 1999

Senior Member

> pro event_handler,ev
> widget_control,ev.top,get_uvalue=infostruct,/NO_COPY
> ...[handle event: make sure there is no return here!]...
> widget_control,ev.top,set_uvalue=infostruct,/NO_COPY
> end

Or, more aptly:

; make sure there is no return here, or any error or other stoppage

The problem with this NO_COPY method is that if any sort of stop,
including an error, happens while the event is being handled, your widget
program is "broken" and must be restarted, since the info UVALUE has gone
missing. If instead you store state information in a permanent place,
like on the pointer or object heap, you can easily patch up your broken
event code, retall, and continue where you left off. *So* much nicer for
development. I vote to ban /NO_COPY from general recommendation. It's a
bit more cumbersome to replace infostruct.x with (*infoptr).x, which is of
course why object widgets are so attractive (self.x).

JD

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[Message index]

		Re: large info structure? By: Wox on Wed, 03 October 2007 01:06
		Re: large info structure? By: David Fanning on Tue, 02 October 2007 14:35
		Re: large info structure? By: markb77 on Tue, 02 October 2007 14:16
		Re: large info structure? By: Paul Van Delst[1] on Tue, 02 October 2007 14:08
		Re: large info structure? By: David Fanning on Tue, 02 October 2007 13:48
		Re: large info structure? By: markb77 on Tue, 02 October 2007 13:25
		Re: large info structure? By: Michael Galloy on Tue, 02 October 2007 10:52
		Re: large info structure? By: Paul Van Delst[1] on Tue, 02 October 2007 09:56
		Re: large info structure? By: David Fanning on Tue, 02 October 2007 08:42
		Re: large info structure? By: Mike[2] on Fri, 05 October 2007 08:01
		Re: large info structure? By: JD Smith on Thu, 04 October 2007 15:40

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