Path: utzoo!mnetor!uunet!cbmvax!rutgers!sunybcs!bingvaxu!leah!uwmcsd1!ig!agate!ucbvax!CORY.BERKELEY.EDU!dillon
From: dillon@CORY.BERKELEY.EDU (Matt Dillon)
Newsgroups: comp.sys.amiga
Subject: Re: forbid/permit
Message-ID: <8801270740.AA05639@cory.Berkeley.EDU>
Date: 27 Jan 88 07:40:01 GMT
Sender: usenet@ucbvax.BERKELEY.EDU
Lines: 32


	You are doing exactly the right thing.  It is quite kosher to use
Forbid()/Permit() for short periods of time as you are doing.  In this 
particular case, the compiler probably gets it down to one instruction anyway
(but of course you can't *assume* that from the C code).

	Forbid()/Permit() simply disable task switching.  The really voltile
calls are Disable()/Enable() which disable interrupts (and thus task switching
as well).  Disable()/Enable() is used mainly by the OS to, for instance,
make message handling calls atomic.

				-Matt
Your message:

:if (k==0) {
: Forbid();
:wdw->flags &= RMBTRAP;
:Permit();
:}
:
:My question is:
:
:can I use any other way to get the same thing done?  I hear that 
:forbid/permit are not quite "kosher" on the amiga...
:
:What I am trying to do in the above code is make the right mouse button
:trapped only under a certain situation on the screen, and then be able
:to turn off or on the trapping as needed.  wdw is a pointer to my window,
:and the flags are currently set to other codes.  I do not want to disturb
:the other flags.
:
:Hans Bechtel