The Synchronize at a Barrier routine causes the caller to wait at
    the specified barrier. The barrier is in effect from the time the
    first participant calls PPL$WAIT_AT_BARRIER until each member of
    the quorum has issued the call. At that time, the wait concludes
    and all are released for further execution.

    Format

      PPL$WAIT_AT_BARRIER  barrier-id ,flags ,spin

1  –  Arguments

 barrier-id

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

    Barrier-id is returned by PPL$CREATE_BARRIER.

 flags

    OpenVMS usage identifier
    type          longword (unsigned)
    access        read only
    mechanism     by reference
    Specifies options for the wait_at_barrier operation. The flags
    argument is the value of a longword bit mask containing the flag.
    The bit, when set, specifies the corresponding option. Valid
    values for flags are as follows:

    PPL$M_SPIN_WAIT    Indicates that the caller is never to block,
                       but rather to always spin while waiting at
                       this barrier.
    PPL$M_SPIN_        Indicates that the caller wishes to spin for
    COUNTED            a given amount of instructions and then to
                       block.

    The default is block immediately, do not spin at all.

 spin

    OpenVMS usage identifier
    type          long (unsigned)
    access        read only
    mechanism     by reference
    This value must be specified when using the PPL$M_SPIN_COUNTED
    flag and represents a relative time that a process will spin
    before blocking.