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

 signal-arguments

    OpenVMS usage:vector_longword_unsigned
    type:         unspecified
    access:       modify
    mechanism:    by reference, array reference

    Signal argument vector. The signal-arguments argument contains
    the address of an array that is this signal argument vector
    stack.

    See the OpenVMS Programming Concepts Manual for a description of
    the signal argument vector.

 mechanism-arguments

    OpenVMS usage:vector_longword_unsigned
    type:         unspecified
    access:       read only
    mechanism:    by reference, array reference

    Mechanism argument vector. The mechanism-arguments argument
    contains the address of an array that is this mechanism argument
    vector stack.

    See the OpenVMS Programming Concepts Manual for a description of
    the mechanism argument vector.