'NSCharacterSet' may not respond to '-count'

Question

I got a warning message in

NSCharacterSet *myCharSet3 = [NSCharacterSet characterSetWithCharactersInString:query3]; 
int chr_count3;
chr_count3=[myCharSet3 count];

How to fix that warning ?

Answer 1

NSCharacterSet does not officially provide a count method. However in my testing, [myCharSet3 count] actually gives the correct result. So just to get rid of the warning:

chr_count3 = (int)[myCharSet3 performSelector:@selector(count)];

But I don't think it's a good idea.