=over =item uc EXPR X X X =item uc Returns an uppercased version of EXPR. This is the internal function implementing the C<\U> escape in double-quoted strings. It does not attempt to do titlecase mapping on initial letters. See L for that. If EXPR is omitted, uses C<$_>. This function behaves the same way under various pragma, such as in a locale, as L does. =back