ReWrite procedure

  DECLARATION:  ReWrite(F : File; RecSize : Word);

      PURPOSE:  Creates and opens a new file

         UNIT:  System

      REMARKS:  F is a file variable of any type that must have been
                previously associated with an external file by the Assign
                procedure.  RecSize is an  optional word-type expression,
                which may only be specified if the file is untyped.

                If F is a Text file, it becomes Write-Only, and EOF(F) will
                always be TRUE.

                NOTE: With {$I-}, errors are returned through IOResult

  DIFFERENCES:  In 3.0, an empty filename was invalid.
                In 5.0, Assign(F,''), followed by ReWrite(F), will refer
                to the standard input file (standard handle number 1).