lock-id

    OpenVMS usage identifier
    type          longword (unsigned)
    access        read only
    mechanism     by reference
    Identifier of the lock to be seized. The lock-id argument is the
    address of an unsigned longword containing the lock identifier.

    Lock-id is returned by PPL$CREATE_SPIN_LOCK.

 flags

    OpenVMS usage mask_longword
    type          longword (unsigned)
    access        read only
    mechanism     by reference
    Bit mask specifying options for seizing the lock. The flags
    argument is a longword bit mask containing the flag. The valid
    value for flags is as follows:

    PPL$M_NON_         The lock is seized if and only if it can
    BLOCKING           be done without causing the caller to wait
                       (spin). (This can be useful in situations
                       where the cost of waiting for a resource is
                       not desirable, or if the caller merely intends
                       to request immediate access to any one of a
                       number of resources.)