VMS Help RTL Routines, PPL$, PPL$GET_INDEX, Arguments  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 participant-index

    OpenVMS usage longword_unsigned
    type          longword (unsigned)
    access        write only
    mechanism     by reference
    The index of the caller within this application. The participant-
    index argument is the address of an unsigned longword that
    contains this index. This index is assigned at process creation
    time and is unique for each participant.