librpma.7 rpma_atomic_write.3 rpma_conn_apply_remote_peer_cfg.3 rpma_conn_cfg_delete.3 rpma_conn_cfg_get_compl_channel.3 rpma_conn_cfg_get_cq_size.3 rpma_conn_cfg_get_rcq_size.3 rpma_conn_cfg_get_rq_size.3 rpma_conn_cfg_get_sq_size.3 rpma_conn_cfg_get_srq.3 rpma_conn_cfg_get_timeout.3 rpma_conn_cfg_new.3 rpma_conn_cfg_set_compl_channel.3 rpma_conn_cfg_set_cq_size.3 rpma_conn_cfg_set_rcq_size.3 rpma_conn_cfg_set_rq_size.3 rpma_conn_cfg_set_sq_size.3 rpma_conn_cfg_set_srq.3 rpma_conn_cfg_set_timeout.3 rpma_conn_delete.3 rpma_conn_disconnect.3 rpma_conn_get_compl_fd.3 rpma_conn_get_cq.3 rpma_conn_get_event_fd.3 rpma_conn_get_private_data.3 rpma_conn_get_qp_num.3 rpma_conn_get_rcq.3 rpma_conn_next_event.3 rpma_conn_req_connect.3 rpma_conn_req_delete.3 rpma_conn_req_get_private_data.3 rpma_conn_req_new.3 rpma_conn_req_recv.3 rpma_conn_wait.3 rpma_cq_get_fd.3 rpma_cq_get_wc.3 rpma_cq_wait.3 rpma_ep_get_fd.3 rpma_ep_listen.3 rpma_ep_next_conn_req.3 rpma_ep_shutdown.3 rpma_err_2str.3 rpma_flush.3 rpma_log_get_threshold.3 rpma_log_set_function.3 rpma_log_set_threshold.3 rpma_mr_advise.3 rpma_mr_dereg.3 rpma_mr_get_descriptor.3 rpma_mr_get_descriptor_size.3 rpma_mr_get_ptr.3 rpma_mr_get_size.3 rpma_mr_reg.3 rpma_mr_remote_delete.3 rpma_mr_remote_from_descriptor.3 rpma_mr_remote_get_flush_type.3 rpma_mr_remote_get_size.3 rpma_peer_cfg_delete.3 rpma_peer_cfg_from_descriptor.3 rpma_peer_cfg_get_descriptor.3 rpma_peer_cfg_get_descriptor_size.3 rpma_peer_cfg_get_direct_write_to_pmem.3 rpma_peer_cfg_new.3 rpma_peer_cfg_set_direct_write_to_pmem.3 rpma_peer_delete.3 rpma_peer_new.3 rpma_read.3 rpma_recv.3 rpma_send.3 rpma_send_with_imm.3 rpma_srq_cfg_delete.3 rpma_srq_cfg_get_rcq_size.3 rpma_srq_cfg_get_rq_size.3 rpma_srq_cfg_new.3 rpma_srq_cfg_set_rcq_size.3 rpma_srq_cfg_set_rq_size.3 rpma_srq_delete.3 rpma_srq_get_rcq.3 rpma_srq_new.3 rpma_srq_recv.3 rpma_utils_conn_event_2str.3 rpma_utils_get_ibv_context.3 rpma_utils_ibv_context_is_odp_capable.3 rpma_write.3 rpma_write_with_imm.3

NAME

rpma_cq_get_fd - get the completion queue's file descriptor

SYNOPSIS

      #include <librpma.h>

      struct rpma_cq;
      int rpma_cq_get_fd(const struct rpma_cq *cq, int *fd);

DESCRIPTION

rpma_cq_get_fd() gets the file descriptor of the completion queue (CQ in short). When a next completion in the CQ is ready to be consumed by rpma_cq_get_wc(3), the notification is delivered via the file descriptor. The default mode of the file descriptor is blocking but it can be changed to non-blocking mode using fcntl(2). The CQ is either the connection's main CQ or the receive CQ or CQ of shared RQ, please see rpma_conn_get_cq(3), rpma_conn_get_rcq(3) or rpma_srq_get_rcq() for details.

Note after spotting the notification using the provided file descriptor you do not have to call rpma_cq_wait(3) before consuming the completion but it may cause that the next call to rpma_cq_wait(3) will notify you of already consumed completion.

RETURN VALUE

The rpma_cq_get_fd() function returns 0 on success or a negative error code on failure. rpma_cq_get_fd() does not set *fd value on failure.

ERRORS

rpma_cq_get_fd() can fail with the following error:

• RPMA_E_INVAL - cq or fd is NULL

SEE ALSO

fcntl(2), rpma_conn_get_cq(3), rpma_conn_get_rcq(3), rpma_srq_get_rcq(3), rpma_cq_wait(3), rpma_cq_get_wc(3), librpma(7) and https://pmem.io/rpma/