header

    OpenVMS usage:octaword_signed
    type:         octaword integer (signed)
    access:       modify
    mechanism:    by reference

    Queue header specifying the queue from which entry will be
    removed. The header argument contains the address of this signed
    aligned octaword integer. The header argument must be initialized
    to zero before first use of the queue; zero means an empty queue.

 remque-address

    OpenVMS usage:address
    type:         quadword (unsigned)
    access:       write only
    mechanism:    by reference

    Address of the removed entry. The remque-address argument is the
    address of an unsigned quadword that contains this address. If
    the queue was empty, remque-address is set to the address of the
    header.

 retry-count

    OpenVMS usage:longword_unsigned
    type:         longword (unsigned)
    access:       read only
    mechanism:    by reference

    The number of times the operation is to be retried in case
    of secondary-interlock failure of the queue instruction in a
    processor-shared memory application. The retry-count argument is
    the address of a longword that contains the retry count value. A
    value of 1 causes no retries. The default value is 10.