=over =item uc EXPR =item uc Returns an uppercased version of EXPR. This is the internal function implementing the C<\U> escape in double-quoted strings. Respects current LC_CTYPE locale if C in force. See L and L for more details about locale and Unicode support. It does not attempt to do titlecase mapping on initial letters. See C for that. If EXPR is omitted, uses C<$_>. =back