cjdb@sphinx.UChicago.UUCP (Charles Blair) (10/31/86)
Does anyone know how the keypress combination Alt-PrtSc could be detected by an applications program? Is it possible? The combination by itself seems not to have a scan code associated with it. However, I know how to detect when the Alt key has been pressed, and an unshifted PrtSc has a scan code of 55. I tried using this knowledge (perhaps naively) to try and detect when Alt and PrtSc were simultaneously depressed, but to no avail. Is what I am attempting possible? Any responses would be appreciated. -- Charles Blair ..!ihnp4!gargoyle!sphinx!cjdb The University of Chicago lib.cb%chip@UChicago.Bitnet
jrv@siemens.UUCP (11/04/86)
Looking at the IBM Tech reference the Alt-PrtSc combination is suppressed
in the keyboard interrupt handler (int 9h). For you to get access to it
you would need to provide a substitute for this interrupt handler
which would provide all the functions of the ROM BIOS routine and generate
something for the key sequence you are interested in.
So as not to have to duplicate all of the IBM functionality it may be
possible to just look for the PrtSc scan code and process it when the
Alt key is depressed. For all other codes use the IBM routine to process
the data. This then requires you to create your own keyboard buffer which
gets characters from your special processing of certain key sequences and
also from the IBM keyboard buffer for all those keys processed by the
IBM BIOS routine. Then since you have your own keyboard buffer you will have
to provide your own int 16h routine so that most applications can get
access to keyboard data.
Jim Vallino
Siemens Research and Technology Lab.
Princeton, NJ
{allegra,ihnp4,seismo,philabs}!princeton!siemens!jrv