Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!jarthur!wilkins
From: wilkins@jarthur.Claremont.EDU (Mark Wilkins)
Newsgroups: comp.sys.mac.programmer
Subject: Background-only applications
Message-ID: <7993@jarthur.Claremont.EDU>
Date: 31 Jul 90 18:17:07 GMT
Organization: Harvey Mudd College, Claremont, CA 91711
Lines: 35



  My firm, an Apple Partner, is working on an image processing package
which, in the manner of, say, Mathematica, permits a user to run a user
interface engine on one machine and perform actual computational tasks on
another machine.

  We wish to implement the processing server as a background-only
application, but the various publications on MultiFinder don't really
address certain issues in implementing such things.

  First:  What operating system managers need to be initialized for a
background-only application to operate?  Are there any which need to be
initialized beyond the minimum necessary to call WaitNextEvent?

  Second:  Is calling WaitNextEvent the correct way for a background-only
app to yield time to other applications?  I note that the Programmer's Guide
to MultiFinder claims that "background-only apps have no user interface..."
does this mean that they can't receive events at all?

  Finally:  Are there pitfalls to launching a background-only app or
restrictions on its operation which would make it useless for our purpose?
Can a user just double-click on a bg-only app or must it be launched by some
other, regular application?

  If I can ever get any of this working, I will be happy to share my
discoveries with anyone who's interested...  Please E-mail and I will
summarize for the network.


-- Mark Wilkins
   INTERNET: wilkins@jarthur.claremont.edu      AppleLink: MARK.WILKINS

   Programmer and Apple Technical Contact,
   SpectroComp Software and Consulting.