Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!lll-winken!uunet!portal!atari!kbad From: kbad@atari.UUCP (Ken Badertscher) Newsgroups: comp.sys.atari.st Subject: Re: Handling mouse button pushes Summary: Use vex_butv() rather than line-a for custom mouse button monitoring. Keywords: Line A, events, debouncing, buttons Message-ID: <1421@atari.UUCP> Date: 2 Apr 89 02:52:48 GMT References: <8086@chinet.chi.il.us> Reply-To: kbad@atari.UUCP (Ken Badertscher) Organization: Atari Corp., Sunnyvale, CA Lines: 29 In article <8086@chinet.chi.il.us> saj@chinet.chi.il.us (Stephen Jacobs) writes: |[stuff about evnt_multi problems monitoring mouse buttons deleted] |1) Use the documented extended Line A variable to sense the mouse button | state whenever it might be interesting. A better solution than using line A variables is to use the VDI vex_butv() call, inserting an interrupt handler of your own which saves the button states in your local variables and passes off to the original vector. After you have installed your handler via vex_butv(), the system will jsr to your code any time the mouse buttons' state changes. When you are done updating your local variables, you should jump through the vector that was returned by vex_butv() so that the system gets the button state change information as well. This is just a pet peeve of mine; people tend to indiscriminantly use the line-A variables rather than the VDI calls that are there. In most cases, it is not necessary (and sometimes dangerous) to use Line A variables. In this particular case, even if you're being very conservative with what you do with button changes, you may run into problems. The AES maintains its own button state information which is independant of the VDI/Line-A variables, and it is possible (if you aren't careful) to get "out of sync" with the AES. Good luck with your button handling code, Stephen! -- Ken Badertscher | #include Atari R&D | No pith, just a path: Software Engine | {portal,ames,imagen}!atari!kbad