.TH "RDMA_JOIN_MULTICAST" 3 "2008-01-02" "librdmacm" "Librdmacm Programmer's Manual" librdmacm
.SH NAME
rdma_join_multicast \- Joins a multicast group.
.SH SYNOPSIS
.B "#include <rdma/rdma_cma.h>"
.P
.B "int" rdma_join_multicast
.BI "(struct rdma_cm_id *" id ","
.BI "struct sockaddr *" addr ","
.BI "void *" context ");"
.SH ARGUMENTS
.IP "id" 12
Communication identifier associated with the request.
.IP "addr" 12
Multicast address identifying the group to join.
.IP "context" 12
User-defined context associated with the join request.
.SH "DESCRIPTION"
Joins a multicast group and attaches an associated QP to the group.
.SH "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, any associated QP is automatically attached to the
multicast group, and the join context is returned to the user through
the private_data field in the rdma_cm_event.
.SH "SEE ALSO"
rdma_leave_multicast(3), rdma_bind_addr(3), rdma_resolve_addr(3), rdma_create_qp(3),
rdma_get_cm_event(3)