VMS Help MACRO, VAX MACRO Assembler, Directives, .NCHR  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Determines the number of characters in a specified character
    string.

      .NCHR symbol,<string>

    symbol

    A symbol that is assigned a value equal to the number  of
    characters in the specified character string.

    <string>

    A sequence of printable characters.   Delimit  the  character
    string with angle brackets (or a character preceded by a
    circumflex) only if the specified character string contains  a
    legal  separator  (comma, space, and/or tab) or a semicolon.

    It can appear anywhere in a  VAX  MACRO  program  and  is  useful
    in calculating the length of macro arguments.