Question

I have found a strange as for me way to declare a method in Objective C.

Method declaration in .h file:

-(void)methodName:(NSString *)str, int i;

Method implementation in .m file:

-(void)methodName:(NSString *)str, int i
{
     NSLog(@"str = %@, int = %d", str, i);
}

I can call this method like this:

[self methodName:@"stringExample", 99];

And it would work fine.

My question is when should I use such syntax. Is there any difference between it and usual declaration?

Answer 1

As described here, those parameters are optional:

Methods that take a variable number of parameters are also possible,
though they’re somewhat rare. Extra parameters are separated by commas
after the end of the method name. (Unlike colons, the commas are not
considered part of the name.) In the following example, the imaginary
makeGroup: method is passed one required parameter (group) and three
parameters that are optional:

[receiver makeGroup:group, memberOne, memberTwo, memberThree];

So yes, the declaration is different to the usual declaration. I cannot find any regular use of this type of declaration other than with a varargs method, where the optional parameter is declared as ....