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From: russotto@eng.umd.edu (Matthew T. Russotto)
Newsgroups: comp.sys.mac.programmer
Subject: Re: StripAddress() question
Message-ID: <1990Nov19.211544.26524@eng.umd.edu>
Date: 19 Nov 90 21:15:44 GMT
References: <90323.102417CXT105@psuvm.psu.edu>
Sender: news@eng.umd.edu (The News System)
Organization: College of Engineering, Maryversity of Uniland, College Park
Lines: 39

In article <90323.102417CXT105@psuvm.psu.edu> CXT105@psuvm.psu.edu (Christopher Tate) writes:
>Do I need to call StripAddress() in the following situation?  Here's the
>relevant code:
>
>Handle        myHand;
>unsigned char *myPtr;
>
>myHand = NewHandle(AMOUNT);
>HLock(myHand);
>myPtr = StripAddress(*myHand);    /* <-- do I need to do this? */
>/* Now, put stuff into the block, using and incrementing myPtr */
>
>Do I need to call StripAddress(*myHand) to make sure I get a valid
>pointer into the block?  I *think* I do, because the master pointer
>might have strange stuff in it, but I'm not sure, and the tech note
>isn't too clear on this....

No.  Not in this case.  What will happen here is
IF 32-bit memory manager is running THEN
  no garbage in master ptr
ELSE (24 bit memory manager)
  garbage is ignored by MMU.

You would need it if you put the MMU in 32 bit mode when under a 24-bit
memory manager, i.e.

Handle        myHand;
unsigned char *myPtr;
extern Ptr hugebitmap /* 32-bit pointer into NuBus address space */

myHand = NewHandle(AMOUNT);
HLock(myHand);
myPtr = StripAddress(*myHand); 
oldmmumode = SwapMMUMode(32bitconstantwhateverthatis);
BlockMove(hugebitmap, myHand, amount);
SwapMMUMode(oldmmumode);
--
Matthew T. Russotto	russotto@eng.umd.edu	russotto@wam.umd.edu
     .sig under construction, like the rest of this campus.