Perl Regular Expression - What does gc modifier means?

I have a regex which matches some text as:

$text =~ m/$regex/gcxs

Now I want to know what gc modifier means:

I have searched and found that gc means "Allow continued search after failed /g match".

This is not clear to me. What does continued search means?

As far as I have understood, it means that start matching at the beginning if the /g search fails. But doesn't /g modifier matches the whole string?