Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!ames!apple!farrier
From: farrier@Apple.COM (Cary Farrier)
Newsgroups: comp.sys.apple
Subject: Re: A few IIGS programming questions
Message-ID: <33512@apple.Apple.COM>
Date: 27 Jul 89 15:39:49 GMT
References: <10294@boulder.Colorado.EDU>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 65

In article <10294@boulder.Colorado.EDU> hartkopf@tramp.Colorado.EDU (HARTKOPF JEFFREY M) writes:
>1)  How can you lock/unlock files from a IIGS desktop application?  Destroy()
>returns an error if I attempt to use it on a locked file.

	From a desktop application, such as the Finder, you can select the
	icon of the file, then choose "Icon Info" under the "Special"
	menu, and it will bring up information about the file.  In the
	upper right hand portion of the information window is a check
	box called "Locked".  You can change the locked status of the
	file by toggling the check box (an "X" in the check box means
	that the file is locked).

	As for not being able to Destroy() a file:

	Each file on a ProDOS volume has an access attribute, which is a
	word value and is defined as follows:

		bits 15-8	reserved, must be zero
		bit 7		0 = destroy disabled, 1 = destroy enabled
		bit 6		0 = rename disabled, 1 = rename enabled
		bit 5		0 = backup not needed, 1 = backup needed
		bits 4-3	reserved, must be zero
		bit 2		0 = file is visible, 1 = file is invisible
		bit 1		0 = write disabled, 1 = write enabled
		bit 0		0 = read disabled, 1 = read enabled

	What you want to do is set the access parameter of the file so that
	bit 7 is a 1, thus enabling you to destroy the file.  Another reason
	that you may not be able to destroy the file is if it is currently
	open.

>2)  What is the format for the createDate, createTime, modDate, and modTime
>fields of some of the ProDOS 16 records?

	The createDate and modDate parameters are both words and
	follow this format:

		bits 15-9	year (1=1901, 2=1902,...)
		bits 8-5	month (1=January, 2=February,...)
		bits 4-0	day of month (1,2,...,31)

	So if you wanted to represent July 27th, 1989, you would use the
	following binary value:

		1011001011111011

	or in hex: B2FB, decimal 45819.

	The createTime and modTime parameters are also word values 
	and follow this format:

		bits 15-13	0
		bits 12-8	hour (0-23)
		bits 7-6	0
		bits 5-0	minute (0-59)

	So if you wanted to represent the time 8:41 (notice that the time
	is expressed using a 24 hour clock), you would use the binary
	value of %0000100000101001, hex $0829, decimal 2089.
 
Cary Farrier
+------------------------------------+
| #include "All.Standard.Disclaimers"|
+------------------------------------+