librpma API version 0.13.0

librpma.7 rpma_atomic_write.3 rpma_conn_apply_remote_peer_cfg.3 rpma_conn_cfg_delete.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_timeout.3 rpma_conn_cfg_new.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_timeout.3 rpma_conn_delete.3 rpma_conn_disconnect.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_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_utils_conn_event_2str.3 rpma_utils_get_ibv_context.3 rpma_utils_ibv_context_is_odp_capable.3 rpma_write.3 rpma_write_atomic.3 rpma_write_with_imm.3


rpma_read - initiate the read operation


      #include <librpma.h>

      struct rpma_conn;
      struct rpma_mr_local;
      struct rpma_mr_remote;
      int rpma_read(struct rpma_conn *conn,
                      struct rpma_mr_local *dst, size_t dst_offset,
                      const struct rpma_mr_remote *src,  size_t src_offset,
                      size_t len, int flags, const void *op_context);


rpma_read() initiates transferring data from the remote memory to the local memory. To read a 0 bytes message, set src and dst to NULL and src_offset, dst_offset and len to 0.

The attribute flags set the completion notification indicator:

  • RPMA_F_COMPLETION_ON_ERROR - generate the completion on error

  • RPMA_F_COMPLETION_ALWAYS - generate the completion regardless of result of the operation.

op_context is returned in the wr_id field of the completion (struct ibv_wc).


The rpma_read() function returns 0 on success or a negative error code on failure.


rpma_read() can fail with the following errors:

  • RPMA_E_INVAL - conn == NULL || flags == 0

  • RPMA_E_INVAL - dst == NULL && (src != NULL || src_offset != 0 || dst_offset != 0 || len != 0)

  • RPMA_E_INVAL - src == NULL && (dst != NULL || src_offset != 0 || dst_offset != 0 || len != 0)

  • RPMA_E_PROVIDER - ibv_post_send(3) failed


rpma_conn_req_connect(3), rpma_mr_reg(3), rpma_mr_remote_from_descriptor(3), librpma(7) and

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