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Re: Why does NSArray count return NSUInteger?
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Re: Why does NSArray count return NSUInteger?


  • Subject: Re: Why does NSArray count return NSUInteger?
  • From: Dave Zarzycki <email@hidden>
  • Date: Mon, 30 May 2011 13:56:38 -0700

On May 30, 2011, at 1:45 PM, julius wrote:

>
> On 30 May 2011, at 20:03,Quincey Morris wrote
>>
>> On May 30, 2011, at 08:27, julius wrote:
>>
>>> All I had hoped was that someone on this list might illuminate the issue more than has happened so far.
>>
>> The problem isn't really lack of illumination, but that you're not prepared to accept the consequences of the explanation.
>
> Hilarity and riot.
>
>>
>> Here's my version of the illumination:
>>
> snip
>> -- It at least theoretically provides opportunities for compile-type (== better) error messages if you accidentally pass a value of the wrong type.
>>
>> -- It at least theoretically eliminates the need to code some range validation checks.
>>
>
> Here is a nice instance that I think quite germane.
>
> The input parameter to NSArray's objectAtIndex: is an NSUInteger.
> Both these code snippets work perfectly (they retrieve element 3).
> 	zStr = [zAry objectAtIndex:3.1];
> and
> 	CGFloat zF1 = 3.2;
> 	zStr = [zAry objectAtIndex:zF1];
>
> I'm sure that by setting the right flags one could get warning messages to appear.


Julius,

As others have pointed out, this has nothing to do with Objective-C or Cocoa. This behavior is true of any C derived language or library. If this aspect of C bothers you, then please consider adding -Wconversion to your project's build settings (CFLAGS):

$ clang -Wall -Wextra -Wconversion -Os -c test.c
test.c:2:18: warning: implicit conversion turns literal floating-point number into integer: 'double' to 'unsigned int'
      [-Wliteral-conversion]
void g(void) { f(3.1); f(-1); }
               ~ ^~~
test.c:2:26: warning: implicit conversion changes signedness: 'int' to 'unsigned int' [-Wsign-conversion]
void g(void) { f(3.1); f(-1); }
                       ~ ^~
2 warnings generated.
$



davez


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