You are viewing the version of this documentation from Perl 5.16.1. View the latest version

Returns an uppercased version of EXPR. This is the internal function implementing the \U escape in double-quoted strings. It does not attempt to do titlecase mapping on initial letters. See "ucfirst" for that.

If EXPR is omitted, uses $_.

This function behaves the same way under various pragma, such as in a locale, as "lc" does.