BOOL vs Boolean

Question

What is the difference between BOOL and Boolean in Objective C ?

Does it matter which one is used?

If not, why do they both exist?

Thanks

Answer 1

There's no functional difference¹ between Objective-C's BOOL data type and the various flavors of boolean types provided by, e.g., stdbool.h for C. However, idiomatic Objective-C code uses the BOOL type (and the values YES and NO) for boolean values.

^{1. There are some differences. For example, a BOOL is actually a signed char, whereas (on my machine) stdbool.h defines _Bool_ and bool to be an int.}