You are viewing the version of this documentation from Perl blead. This is the main development branch of Perl. (git commit bb3b5a6b4200a22651478e4804c30dcb289d6c3f)
${^PREMATCH}

It is only guaranteed to return a defined value when the pattern was executed with the /p modifier.

This is similar to $` ($PREMATCH) except that to use it you must use the /p modifier when executing the pattern, and it does not incur the performance penalty associated with that variable.

See "Performance issues" above.

This variable was added in Perl v5.10.0.

This variable is read-only, and its value is dynamically scoped.