Is there a constant for the maximum CGFloat value?

Question

I need to create a CGSize to compute text height of an arbitrary text with arbitrary length. UIKit has this nice method -sizeWithFont:constrainedToSize: and my text is only cons

Answer 1

This is more of a comment than an answer however I don't have enough reputation to comment at the present.

I just came across unexpected behavior with using CGFLOAT_MAX: on an iPhone 5S (64bit) device running iOS 7.1.2 and using Xcode 5.1.1, the following code:

CGFloat numRot = floorf(CGFLOAT_MAX / 360.0);
NSLog(@"numRot = %.2f", numRot);

Outputs:

numRot = inf

Whereas, this code:

CGFloat numRot = floorf(FLT_MAX / 360.0);
NSLog(@"numRot = %.2f", numRot);

Correctly outputs:

numRot: 945228740662580166143622731901435904.00

I command+clicked on the CGFLOAT_MAX and Xcode took me to the CoreGraphics frameworks CGBase.h file with the following macro definition:

# define CGFLOAT_MAX DBL_MAX

I command+clicked on CGFloat and Xcode took me to another line in the same file:

typedef CGFLOAT_TYPE CGFloat;

Then I command+clicked on the CGFLOAT_TYPE and it jumped to the #define line here:

#if defined(__LP64__) && __LP64__
# define CGFLOAT_TYPE double
...

So, for some reason my CGFloat variable is supposed to be a double, however it appears to be a float that overflows when it gets assigned a double value (i.e. CGFLOAT_MAX). As far as I can tell this Apple documentation page indicates using %f with NSLog should print the double - someone please correct me if this is wrong.

All that to say, if FLT_MAX works for your case, you may want to stick with that for now instead of CGFLOAT_MAX, especially if you are relying on a library that specifically accept float arguments instead of double or CGFloat.