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From: apsh AT ecr DOT mu DOT oz DOT au (Alistair_P SHILTON)
Subject: keyboard problem with allegro (printscreen)
Newsgroups: comp.os.msdos.djgpp
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Date: Fri, 11 Feb 2005 05:24:47 GMT
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To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com

Hi

I'm having some peculiar troubles with the "print screen" button in allegro 
(DJGPP version), which I'd like to use it for a screen capture function, and 
was wondering if this is a known issue.  The problem occurs in an emulator 
I've written (code online at http://www2.ee.mu.oz.au/pgrad/apsh/microbee/ -
see mbee32k.c, relevant function key_lowlevel_stuff).  I've set
keyboard_lowlevel_callback to my function key_lowlevel_stuff to catch key 
press and release, and everything works fine for most keys (callback function 
is called for press and release with an appropriate scancode) - except when 
PRT_SCR is pressed.  When PRTSCR is pressed on it's own, the callback function 
is usually not called at all, except very occasionally when it is called with 
the release scancode KEY_PRTSCR | 0x080.  Oddly, if control-PTRSCR is pressed 
then the PRTSCR scancode gets through as expected.

I've tried everything I can think of, and googling seems to draw a blank.  Any 
thoughts?  I know I could just use a different key for the purpose, but 
printscreen seems to be the logical choice, and also is one of only 5 keys 
present on the my pc keyboard but not on later model microbees, which is what 
I'm planning to emulate, so I'd prefer to use it if possible.

tia


--
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Alistair Shilton

http://www2.ee.mu.oz.au/pgrad/apsh/microbee/