Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!TMASL.EXXON.COM!FERGUSON
From: FERGUSON@TMASL.EXXON.COM
Newsgroups: comp.sys.apollo
Subject: Opening a stream to nil files
Message-ID: <8906211239.AA02260@umix.cc.umich.edu>
Date: 21 Jun 89 12:35:00 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 18


To access files with type nil, you must use the Mapped Segment Manager,
or ms_$ calls. The call, ms_$mapl, will open the file, and you can
directly map whatever byte you want in the file to a pointer in your
program.

This is nice for many reasons. One is that you never have to perform
a 'read' of the data. You just get a pointer to the actual disk file,
and do with it what you want. Also, it's the only way I know to work with
'nil' files.

Fonts are 'nil' files, and I had always hoped that Apollo would provide a
set of system calls for working with fonts. Edfont is nice, but for
translating non-apollo fonts to apollo format would take a year by hand.

Good Luck
Scott Ferguson
ferguson@erevax.bitnet