Apr 95 Dialog Box
|Column Tag:||Dialog Box
By Scott T Boyd, Editor
Jasik Has A Better Bus Error
Steve Jasik wrote, in light of the attention weve been giving to the need to use strong debugging tools, to remind us that his Debugger has been putting a garbage value in location zero since its inception, and you get the message if you trip on it.
He also wanted to remind us that it has a version of Trap Discipline similar to the one implemented in TMON, but it also does the Color QD Traps. His version of Discipline will catch double disposes, etc. He says its supported (and documented?).
- Ed stb
Stenger Goes For Two Months In A Row
I found a couple of cases where Bob Boonstras solution to the Rubiks Cube challenge (MacTech, February 1995, pp. 49 ff.) goes into a loop.
(1) If the cube is already solved, the code correctly detects that no moves are necessary, but the playback loop in SolveRubiksCube doesnt handle this empty case correctly (the loop is coded to execute at least once).
(2) The illegally-colored cube with solid faces 0, 3, 4, 2, 1, 5 is not caught by LegalCube, and then generates no moves (I dont know why this is). It then fails as in item (1).
The code works correctly on all the normal cases I tried, so it meets the spirit of the Challenge and should still be the winner.
- Allen Stenger, email@example.com
Prograph - Wheres It Been Hiding?
I read Kurt Schmuckers article on Prograph CPX, and was amazed that I had never heard of this product. I am a programmer for a consulting company here in Milwaukee. After reading that article, I went out and bought Prograph CPX immediately. I want to see more articles about Prograph - I think its a product that has a great future.
- minton brooks, MBAssoc@aol.com
Re: A Quick Trip Into the Depth
In his article in the February issue, A Quick Trip Into the Depths, Steve Jasik writes, The crux of the problem was that, despite what Inside Macintosh or todays equivalent of it says, the Resource Manager doesnt always return a non-zero value of ResErr when it doesnt find the requested resource.
This assertion is incorrect. Inside Macintosh does specifically warn you about this problem. Inside Macintosh : More Macintosh Toolbox on page I-51 in describing ResError function has this to say under the caption IMPORTANT, In certain cases, the ResError function returns noErr even though a Resource Manager routine was unable to perform the requested operation. See the individual routine descriptions for details about the circumstances under which this happens.
Then if we turn to page I-73 of the same volume, we can read that, If you call GetResource with a resource type that cant be found in any of the resource maps of the open resource forks, the function returns NIL, but ResError returns the result code noErr. You should always check that the value of the returned handle is not NIL.
- Vladimir Potap'yev, VolodyaP@aol.com
We Forgot To Say Thanks!
Chris De Salvo contributed Control Strip Tester - an application shell to help you test out control strips - to go along with Mike Blackwells Writing Control Strip Modules article in our December issue. We didnt have time to get a mention of it into the issue, but we did manage to get it onto our source disk and our online sites. You can find it at:
and our other online sites, and you can e-mail him at firstname.lastname@example.org.
- Ed stb