Re: Crash in CopyBits on OS X

Could be a case where the BBSlab blitter reads past the end of the source buffer (to align its long-reads).

Of course, could be anything else, too :-)

Check out http://developer.apple.com/releasenotes/DeveloperTools/MallocOptions.html

and "man libgmalloc".

--(jm)

On Jul 28, 2005, at 10:30 AM, Bill Patterson wrote:

From: email@hidden
Subject:
Date: July 28, 2005 01:29:44 PM EDT
To: email@hidden

I'm getting an intermittent crash in OS X, at least 10.2 and 10.4 with a call to CopyBits.

The call stack for the crash is below:
Thread 0 Crashed:
#0 0x91a56ab8 in BBSlab
#1 0x91a543a4 in Stretch
#2 0x91a5f168 in OneSrcOneDst
#3 0x91a59a90 in BitsDevLoop
#4 0x91a53868 in CommonBits
#5 0x91a59c88 in CopyBits (toolbox call)
#6 0x00853c04 in vdrawsysImageMask (my code)

The destination is a one-bit/pixel GWorld.

GWorld PixMap as follows:

rowBytes is 0x8010
bounds 0, 0, 42, 17
pmVersion 1
packType 0
packSize 0
hRes 4718592
vRes 4718592
pixelType 0
pixelSize 1
cmpCount 1
cmpSize 1
pixelFormat 1

I tried forcing the gworld and source and destination rect's to multiple-of-4 sizes, with no effect. In this case, it made all the rects 20 pixels wide. Still crashed intermittently.

I also make sure the gworld is set and gdevice is set.

Same call works most of the time, but occasionally crashes as above. Crash is always in same GWorld, the size shown. Other calls, sometimes also with odd sizes, work without ever crashing.

Maybe unrelated, but other times CopyBits just goes into the ether, never drawing. No crash, just no visible effect. Again, intermittent, although this happens much more frequently than crashes, like 1 out of 3 times.

Anybody know what this is?

Thanks,

Bill Patterson

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References:
	>Crash in CopyBits on OS X (From: Bill Patterson <email@hidden>)