Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!samsung!think!snorkelwacker!apple!archer!dwb
From: dwb@archer.apple.com (David W. Berry)
Newsgroups: comp.sys.mac.programmer
Subject: Re: StripAddress...
Message-ID: <6521@internal.Apple.COM>
Date: 5 Feb 90 21:53:37 GMT
References: <1990Feb2.010425.28126@oracle.com>
Sender: usenet@Apple.COM
Organization: Apple Computer
Lines: 44

In article <1990Feb2.010425.28126@oracle.com> gstein@oracle.uucp (Gregory Stein) writes:
>[ I posted this once before and received no response, so I'm trying
>  again... ]
>
>    struct foo {
>	int a, b, c;
>    } **bar;
>    bar = (struct foo **) NewHandle(sizeof(struct foo));
>
>Now, when I say "(*bar)->a" is this 32-bit clean?  For this example
	Yes.  If the flag bits are in the upper byte, the memory
mapping hardware will be set to ignore the upper byte.  If full
32 bit addresses are being used, the flags will be kept somewhere
other than the upper byte.  The primary things to remember to
be 32 bit clean are:

1.  Don't use bset/bclr to change or access flag bytes.  Use HLock,
HGetState, etc.

2.  Don't fake handles.  A handle and an &Pointer aren't the same thing.
If you want to include your custom ?DEF in line in your program the
following routine is real handy:

	ProcHandle ProcToHandle(ProcPtr proc)
	{
		struct ProcJmp {
			short		jmp;
			ProcPtr		addr;
		} **hand;

		hand = (struct ProcJmp **) NewHandle(sizeof(**hand));
		(**hand).jmp = 0x4ef9;
		(**hand).addr = StripAddress(proc);	/* excessive paranoia */

		return (ProcHandle) hand;
	}

3.  Don't try to walk the zone.  The zone format is subject to change.
If it changes you'll likely blow up.

4.  Use GetWVariant and GetCVariant instead of using the upper byte
of the definition routine.  If you have to set the variant be real
careful, remember to check for an auxilliary record and change the
variant there if it exists.  If not set it in the upper byte.