ibv_attach_mcast, ibv_detach_mcast - attach and detach a queue pair
(QPs) to/from a multicast group
SYNOPSIS
#include <infiniband/verbs.h>int ibv_attach_mcast(struct ibv_qp *qp, const union ibv_gid *gid, uint16_t lid);int ibv_detach_mcast(struct ibv_qp *qp, const union ibv_gid *gid, uint16_t lid);
DESCRIPTION
ibv_attach_mcast()
attaches the QP
qp
to the multicast group having MGID
gid
and MLID
lid.
ibv_detach_mcast()
detaches the QP
qp
to the multicast group having MGID
gid
and MLID
lid.
RETURN VALUE
ibv_attach_mcast()
and
ibv_detach_mcast()
returns 0 on success, or the value of errno on failure (which indicates the failure reason).
NOTES
Only QPs of Transport Service Type
IBV_QPT_UD
may be attached to multicast groups.
If a QP is attached to the same multicast group multiple times, the QP will still receive a single copy of a multicast message.
In order to receive multicast messages, a join request for the
multicast group must be sent to the subnet administrator (SA), so that
the fabric's multicast routing is configured to deliver messages to
the local port.