Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!gem.mps.ohio-state.edu!apple!farrier
From: farrier@Apple.COM (Cary Farrier)
Newsgroups: comp.sys.apple
Subject: Re: GS/OS calls--how?
Message-ID: <4716@internal.Apple.COM>
Date: 12 Oct 89 23:27:36 GMT
References: <12696@boulder.Colorado.EDU>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 45

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.
>
>For example, to get file info on a file, I did something like
> [...example deleted...]
>
>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?
>
>When I did the above, I just seemed to get garbage values for the fileType,
>access, auxType, createDateTime, modDateTime, etc., fields.  What am I doing
>wrong?  Do any other fields besides pathname and pCount have to be pre-set 
>before I call GetFileInfoGS()?


	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.

Cary Farrier


-- 
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| Cary Farrier | farrier@apple.com       |
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