user-context

    OpenVMS usage:context
    type:         longword (unsigned)
    access:       modify
    mechanism:    by reference

    User context that retains the translation context over multiple
    calls to the date/time input and output formatting routines.
    The user-context argument is the address of an unsigned longword
    that contains this context. If the user-context argument was not
    specified in the call to LIB$FORMAT_DATE_TIME, LIB$CONVERT_DATE_
    STRING, or LIB$GET_MAXIMUM_DATE_LENGTH, then no argument should
    be supplied when calling this routine.