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From: dlyons@Apple.COM (David Lyons)
Newsgroups: comp.sys.apple
Subject: Re: GS/OS calls--how?
Message-ID: <35642@apple.Apple.COM>
Date: 14 Oct 89 06:44:49 GMT
References: <12696@boulder.Colorado.EDU> <4716@internal.Apple.COM>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 52

>In article <12696@boulder.Colorado.EDU> hartkopf@tramp.Colorado.EDU (Jeff Hartkopf) writes:
>>I'm attempting to learn how to use GS/OS calls, and have come up with  
>>some questions.  Things don't seem to be working the same way as they did
>>with the ProDOS 16 calls.

The main reason for this is that the GS/OS (class 1) calls are *not* the
same as the ProDOS 16 (class 0) calls. :-)    (If they were they same,
we wouldn't need two kinds of calls, eh?)

>>At first I didn't assign anything to the pCount variable and kept
>>getting errors, so after a little experimentation, I found that 2 seems
>>to work.  But what is the pCount field of most of the GS/OS records for?

For GetFileInfoGS, use pCount=12 to get back all the information that the
current version of GS/OS can return for that call.

BTW, it will probably help a bunch if you buy the GS/OS reference from
APDA.


Cary Farrier writes:
>	The pcount field in the Class 1 GS/OS system calls tells the
>	system how many parameters are in your pblock.  The format
>	for the class 1 GET_FILE_INFO call is:
>
>		$00-$01		pcount
>		$02-$05		input pointer to a class 1 input string
>				containing the pathname
>		$06-$07		access
>		$08-$09		file_type
>		$0A-$0D		aux_type
>		... [and so on...]
>
>	When you specify a pcount of 2, you are telling the system
>	that you only want to give it the pathname and to receive
>	the file_type. A pcount of 3 will include the aux_type, and
>	so on.  Since you only specify a pcount of 2, the FST will
>	not fill in any parameters other than the first two.  Note
>	that the pcount does not include pcount itself.
>
Looks like 2 will get you only the Access parameter back (the input
pathname counts as the first parameter), so 3 will get you the Access
and Filetype.
-- 

 --Dave Lyons, Apple Computer, Inc.          |   DAL Systems
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