state VARLIST
    state TYPE VARLIST
    state VARLIST : ATTRS
    state TYPE VARLIST : ATTRS
            "state" declares a lexically scoped variable, just like "my".
            However, those variables will never be reinitialized, contrary
            to lexical variables that are reinitialized each time their
            enclosing block is entered. See "Persistent Private Variables"
            in perlsub for details.

            If more than one variable is listed, the list must be placed in
            parentheses. With a parenthesised list, "undef" can be used as a
            dummy placeholder. However, since initialization of state
            variables in list context is currently not possible this would
            serve no purpose.

            "state" variables are enabled only when the "use feature
            "state"" pragma is in effect, unless the keyword is written as
            "CORE::state". See also feature. Alternately, include a "use
            v5.10" or later to the current scope.