NAME

       rdma_join_multicast - Joins a multicast group.

SYNOPSIS

       #include <rdma/rdma_cma.h>

       int rdma_join_multicast (struct rdma_cm_id *id, struct sockaddr *addr, void *context);

ARGUMENTS

       id          Communication identifier associated with the request.

       addr        Multicast address identifying the group to join.

       context     User-defined context associated with the join request.

DESCRIPTION

       Joins a multicast group and attaches an associated QP to the group.

RETURN VALUE

       Returns  0  on success, or -1 on error.  If an error occurs, errno will be set to indicate
       the failure reason.

NOTES

       Before joining a multicast group, the rdma_cm_id must  be  bound  to  an  RDMA  device  by
       calling  rdma_bind_addr or rdma_resolve_addr.  Use of rdma_resolve_addr requires the local
       routing tables to resolve the multicast address to  an  RDMA  device,  unless  a  specific
       source  address  is  provided.   The  user  must  call  rdma_leave_multicast  to leave the
       multicast group and release any multicast resources.  After the join operation  completes,
       if  a  QP is associated with the rdma_cm_id, it is automatically attached to the multicast
       group when the multicast  event  is  retrieved  by  the  user.   Otherwise,  the  user  is
       responsible  for calling ibv_attach_mcast to bind the QP to the multicast group.  The join
       context is returned to the user through the private_data field in the rdma_cm_event.

SEE ALSO

       rdma_leave_multicast(3),   rdma_bind_addr(3),   rdma_resolve_addr(3),   rdma_create_qp(3),
       rdma_get_cm_event(3)