/sys$common/syshlp/helplib.hlb MMS, Generating Description Files, Qualifiers, /MAIN_MODULE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    /MAIN_MODULE=module-name

    Specifies the main module to be included from the object library
    during the Link process. The main module is that defined in the
    first source file specified and, by default, the module name is
    the same name as the file. This qualifier lets you specify a
    module name that is different from the file name. Note that if an
    appropriate language-dependent module name directive is detected
    within the first source file, the value specified by this
    qualifier is ignored.