On Sep 8, 2010, at 1:29 PM, Greg Parker wrote:
> On Sep 8, 2010, at 12:40 PM, Chris Tracewell wrote:
>> On Sep 8, 2010, at 12:02 PM, cocoa-dev-requ...@lists.apple.com wrote:
>>> It's not YES that's being "returned as" -256, but NO. (The answer is NO in
>>> all 3 cases.) -256 is 0xFFFFFF00, so you can see that NO (i.e. (signed
>>> char) 0) is being correctly returned in the low order byte, with trash in
>>> the high order bytes that's left over from earlier code.
>>>
>>> So, the problem is not your 'isLessThanZero' method, but the calling code,
>>> which is treating the returned value as an int (or something). Presumably
>>> the calling code was compiled with an incompatible declaration of your
>>> method, or of the BOOL type.
>>
>> Thanks Quincey, your suggestion got me looking at the calling model and I
>> got it working by first assigning the result as a BOOL rather than just
>> using the result inside of an if logic statement like so...
>>
>>
>> // ========== Did NOT Work =========//
>>
>> if ([theDecimalNumber isLessThanZero])
>> {
>> ... do something
>> }
>>
>> // ========== DID Work =========//
>>
>> BOOL theResult = [theDecimalNumber isLessThanZero];
>> if (theResult)
>> {
>> ... do something
>> }
>>
>> I must admit that I do not understand why this is so. I can for example use
>> if ([someButton isEnabled]) and it returns a BOOL and the if statement
>> works fine. If you have any pointers or docs that explains this further I
>> would really appreciate it as right now I feel scared about how I have been
>> evaluating BOOL's returned in all of my own custom methods.
>
> I bet you have a compiler warning at this call site that says "warning:
> 'NSDecimalNumber' may not respond to '-isLessThanZero'". That means the
> compiler can't see the method declaration for -isLessThanZero at the call
> site. In that case, the compiler guesses that the method returns `int`, which
> is wrong and will cause incorrect handling of the BOOL value on some
> architectures.
>
> You need to (1) put your category's @interface in a header file, and (2)
> import that header file here.
>
>
> --
> Greg Parker gpar...@apple.com Runtime Wrangler
Greg,
That was it :-) I had not imported ANY category headers in my framework -
"most" had worked anyway in my linking project so I figured it was some
framework magic behind the scenes recognizing them and making them work. After
linking them my warning count went way down and I am getting syntax coloring
now too - bonus!
I wanted to sneak in one last question - is it safe to compare an
NSDecimalNumber to an NSNumber and visa versa?
Thanks for taking the time to respond.
-chris_______________________________________________
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