NULL events and 'txt' in RISC_OSLib

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#913

From: David Alan Gilbert
Date: Tue, 12 Jan 1993 08:46

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Just a warning to all you who are using NULL
events a lot.  As far as I can tell the 'txt'
section of RISC_OSLib changes the event mask to 
allow NULL events when you drag in a window (be it
scroll bar or over the work area).  When it
has finished it then sets the mask to IGNORE
NULL's - no matter what the state previously.

So if your program relied on them a lot, your
program suddenly stops any background activity.

The way I confirmed this was to print event_getmask()
before I called event_process() - it suddenly became
1 after attempting to scroll the window with the
scroll bar - and definitly with a click on the
work area.

Dave
--
-------------------------------------------------------------------------------
- David Alan Gilbert - gilbertd@cs.man.ac.uk - G7FHJ@GB7CRG                   -
------(Programmers don't sleep - they just park their heads)-------------------

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From: gilbertd@cs.man.ac.uk (David Alan Gilbert)
Newsgroups: comp.sys.acorn.tech
Subject: NULL events and 'txt' in RISC_OSLib
Message-ID: <gilbertd.726828391@cs.man.ac.uk>
Date: 12 Jan 93 08:46:31 GMT
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