retrieves a completed send, read, or write request.
(struct rdma_cm_id *id,
struct ibv_wc *wc);
A reference to a communication identifier to check for completions.
A reference to a work completion structure to fill in.
Retrieves a completed work request for a send, RDMA read, or RDMA write
operation. Information about the completed request is returned through
the wc parameter, with the wr_id set to the context of the request. For
details on the work completion structure, see ibv_poll_cq.
Returns the number of returned completions (0 or 1) on success, or -1 on error.
If an error occurs, errno will be set to indicate the failure reason.
This calls polls the send completion queue associated with an rdma_cm_id.
If a completion is not found, the call blocks until a request completes.
This call should only be used on rdma_cm_id's that do not share CQs
with other rdma_cm_id's, and maintain separate CQs for sends and receive