NAME

       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.

SEE ALSO

       ibv_create_qp(3)

AUTHOR

       Dotan Barak <dotanba@gmail.com>