I'm trying to put "bold" on a part of a text, but I can't do it.
I'm using this:
NSMutableAttributedString *string = [[NSMutableAttributedString alloc] initWithString:@"this is a part of the text"];
NSRange selectedRange = NSMakeRange(5, 10);
[string beginEditing];
[string addAttribute:NSFontAttributeName
value:[NSFont fontWithName:@"Helvetica-Bold" size:12.0]
range:selectedRange];
[string endEditing];
I get an error "use of undeclared identifier NSFontAttributeName";
How can I do it?