=over

=item ${^PREMATCH}
X<$`> X<${^PREMATCH}>

This is similar to C<$`> ($PREMATCH) except that it does not incur the
performance penalty associated with that variable, and is only guaranteed
to return a defined value when the pattern was compiled or executed with
the C</p> modifier.

This variable was added in Perl 5.10

This variable is read-only and dynamically-scoped.

=back