m// notes and easy mistakes

m// returns true or false in scalar context, not a character position or a match count!

In array context you get an array of matching strings - even if there is only 1 match, it's an array of 1 element.

m//g is different - it has state, and in scalar context will return true or false as many times as there are matches. Obviously it will only do this if invoked multiple times, eg in a while loop. In array context you get an array (obviously) as above.