Logging a NSUInteger breaks xcode [duplicate] - objective-c

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"Thread 1: stopped at breakpoint" error when initializing an NSURL object
(3 answers)
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I'm doing a tutorial on codeschool http://tryobjectivec.codeschool.com/ and according to this tutorial the following code should work:
void (^sumNumbers)(NSUInteger, NSUInteger) = ^(NSUInteger num1, NSUInteger num2){
NSLog(#"The sum of the numbers is %lu", num1 + num2);
};
Well, I tried the let this work, allthough xcode already gave me some orange error message:
I tried to build the code anyway, just to see if xcode was right or the tutorial was right. Well, something broke:
But even worse, I can't get xcode fixed again, xcode now pretends that all my code that I've ever wrote is causing problems. But I'm pretty sure it used to work:

Answer 1

NSUInteger is, at least in a 32-bit architecture, typedefed as an unsigned int, not a long. The %lu formatter specifies that you want to print them as longs, so there's a type conflict. If you print them as %ud, which is an unsigned int.
The blue marker in the gutter of the line sumNumbers(10,20); indicates that you have a breakpoint set on that line, which causes the interruption of the app. Remove/disable that breakpoint and that will work fine as well.

Answer 2

It is generally advised that you do not use NSInteger, NSUInteger, CGFloat, or CFIndex as direct parameters to an NSLog, or any other operation using a printf-style formatter. The reason is that their size varies between 32 and 64 bit architectures.
In your case, the correct way to write the code is to cast the NSUInteger to an unsigned long which is 64 bits on both architectures, at least as far as the XCode toolchain is concerned. Be warned that this may not be the case on other systems - for example, the C++ standard only requires that a long be at least 32 bits in size.
void (^sumNumbers)(NSUInteger, NSUInteger) = ^(NSUInteger num1, NSUInteger num2){
NSLog(#"The sum of the numbers is %lu", (unsigned long)(num1 + num2));
};
With regard to the tutorial, the person who wrote it was probably working on a 64 bit system, so NSUInteger mapped to the size required by %lu. Everything you read on the Web, from Apple documentation to Stack Overflow answers will have errors somewhere.

Answer 3

In order to NSLog your NSUInteger, you should change your statement to this:
NSLog(#"%ud", num1 + num2);
The reason your app is not running properly anymore is probably because you still have your breakpoint set. Go to Debug > Deactivate Breakpoints or use the shortcut ⌘Y, and then try running your application.