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)