I think wantarray isn't really what the OP wants. He/She wants to know the best way to deal with a function that may return 0, 1 or more answers. Wantarray is helpful for those times when you know you only want one value. I think the OP has a situation where there is usually only 0 or 1 answer, but sometimes more than 1.

For example, if I'm writing a function that returns the name of the hat I'm wearing. The answer is either a name or no name. Suddenly, I realise I sometimes wear more than one hat! Sometimes I wear a lot of hats! How should I write my function? Should I return a scalar when I have zero or one hat, or should I return a list even when I have one or no hats?

The choices are generally to either check what you get from the function or always use a list/array. I generally* agree that it's best to always return a list (or list ref). If you're going to write the stuff to handle a list anyway, you're just adding extra work by writing special stuff to handle scalars. It's also more robust and it scales better. By scales better, I mean, in that one instance where you always get a scalar, you suddenly realise you want a list and you have to rewite a ton of stuff with lots of trickling expectations. Lastly, if you do decide in some special case that you want to deal with a single value differently, it's easy.

Maybe I'm totally wrong about what the OP means though...

* generally folks, I said generally!

--Pileofrogs