Function with COPY command?

Is there any way to make this function work?

CREATE OR REPLACE FUNCTION import_text_file(char(255)) RETURNS void AS $$
DECLARE
     filename ALIAS FOR $1;
BEGIN
     COPY table FROM filename;
END;
$$ LANGUAGE plpgsql;

The version below works fine, but I need something like the above version.

CREATE OR REPLACE FUNCTION import_text_file(char(255)) RETURNS void AS $$
DECLARE
     filename ALIAS FOR $1;
BEGIN
     COPY table FROM 'C:\\somefile.txt';
END;
$$ LANGUAGE plpgsql;


--
Thanks,

Warren