Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!gem.mps.ohio-state.edu!apple!enwall
From: enwall@Apple.COM (Tim Enwall)
Newsgroups: comp.sys.mac.programmer
Subject: Re: serial question
Message-ID: <35526@apple.Apple.COM>
Date: 10 Oct 89 15:56:48 GMT
References: <5727@tank.uchicago.edu>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 28

In article <5727@tank.uchicago.edu> rfl@oddjob.UChicago.EDU (Bob Loewenstein) writes:
>
>I have a program where I use the serial driver at 19200 baud. I
>set the size of the internal buffer to a large block so that I don't
>miss any transmissions while I'm not reading the port (64 bytes, the
>default, is too small). My problem is this: If someone using the program
>decides to open up some terminal emulator desk accessory, or switches
>via multifinder to another program that wants the port, when they
>switch back to my application, always my buffer is no longer used and
>the default is back; sometimes it screws things up altogether and
>causes a bomb.
>

You can use suspend/resume events to get notified when your your application
is being put into the background/foreground and do whatever is necessary to 
save the state of your program.

The "Programmer's Guide to MultiFinder" available from APDA explains suspend
resume events, as do five of the current Tech Notes.

Hope this helps.
-- 
Tim Enwall
Macintosh Developer Technical Support
Apple Computer, Inc.

"Opinion's but a fool, that makes us scan
 The outward habit by the inward man"    -- Pericles, Act II. Sc.2