$num_matches_stuff = $str =~ m/(stuff)/g;
@all_the_matches = $str =~ m/(stuff)/g;
In scalar context we get the count of the matches, in array context we get the matches.
No, the former just is not right. You haven't actually tried it, have you?
$str = "stuff stuff stuff";
$num_matches_stuff = $str =~ m/(stuff)/g;
print $num_matches_stuff;
Result:
1
The /g modifier in scalar context is very special. It is intended to be used in a loop, something like this:
$str = "stuff stuff stuff";
while($str =~ m/(stuff)/g) {
print "Got one!\n";
}
Result:
Got one!
Got one!
Got one!
So in scalar context, it will match at most once at a time — next time around, it'll continue where it left off last time.
Therefore, the returned valued of //g when used in scalar context is either 0, or 1.