=over =item ${^PREMATCH} X<${^PREMATCH}> It is only guaranteed to return a defined value when the pattern was executed with the C</p> modifier. This is similar to C<$`> ($PREMATCH) except that to use it you must use the C</p> modifier when executing the pattern, and it does not incur the performance penalty associated with that variable. See L</Performance issues> above. This variable was added in Perl v5.10.0. This variable is read-only, and its value is dynamically scoped. =back