What does “% is unavailable: Use truncatingRemainder instead” mean?

Question

I get the following error when using code for an extension, I\'m not sure if they\'re asking to just use a different operator or modify the values in the expression based on

Answer 1

The % modulus operator is defined only for integer types. For floating-point types, you need to be more specific about the kind of IEEE 754 division/remainder behavior you want, so you have to call a method: either remainder or truncatingRemainder. (If you're doing floating-point math you actually need to care about this, and lots of other stuff, or you can get unexpected / bad results.)

If you actually intend to do integer modulus, you need to convert the return value of CMTimeGetSeconds to an integer before using %. (Note that if you do, you'll lop off the fractional seconds... depending on where you're using CMTime that may be important. Do you want minutes:seconds:frames, for example?)

Depending on how you want to present CMTime values in your UI, it might be better to extract the seconds value and pass it to NSDateFormatter or NSDateComponentsFormatter so you get appropriate locale support.