SYNOPSIS
cc [
flag... ]
file...
-ldat [
library... ]
#include <
dat/udat.h>
DAT_RETURN
dat_ep_post_recv (
IN DAT_EP_HANDLE ep_handle,
IN DAT_COUNT num_segments,
IN DAT_LMR_TRIPLET *local_iov,
IN DAT_DTO_COOKIE user_cookie,
IN DAT_COMPLETION_FLAGS completion_flags
)
PARAMETERS
ep_handle
Handle for an instance of the Endpoint.
num_segments
Number of lmr_triplets in local_iov. Can be 0 for receiving a 0 size message.
local_iov
I/O Vector that specifies the local buffer to be filled. Can be NULL for receiving a 0 size message.
user_cookie:
User-provided cookie that is returned to the Consumer at the completion of the Receive DTO. Can be NULL.
completion_flags
Flags for posted Receive. The default
DAT_COMPLETION_DEFAULT_FLAG is 0x00. Other values are as follows:
Notification of Completion
DAT_COMPLETION_UNSIGNALLED_FLAG
0x04
Non-notification completion. Local Endpoint must be configured for Unsignaled CompletionNotification Suppression.
DESCRIPTION
The
dat_ep_post_recv() function requests the receive of the data over the connection of the
ep_handle Endpoint of the incoming message into the
local_iov.
The
num_segments parameter specifies the number of segments in the
local_iov. The
local_iov segments are filled in the I/O Vector order until the whole message is received. This ensures that all the "front" segments of the
local_iov I/O Vector are completely filled, only one segment is partially filled, if needed, and all segments that follow it are not filled at all.
The
user_cookie allows Consumers to have unique identifiers for each DTO. These identifiers are completely under user control and are opaque to the Provider. There is no requirement on the Consumer that the value
user_cookie should be unique for each DTO. The
user_cookie is returned to the Consumer in the Completion event for the posted Receive.
The completion of the posted Receive is reported to the Consumer asynchronously through a DTO Completion event based on the configuration of the connection for Solicited Wait and the specified
completion_flags value for the matching Send. The value of
DAT_COMPLETION _UNSIGNALLED_FLAG is only valid if the Endpoint Recv Completion Flags
DAT_COMPLETION_UNSIGNALLED_FLAG. Otherwise,
DAT_INVALID_PARAMETER is returned.
A Consumer must not modify the
local_iov or its content until the DTO is completed. When a Consumer does not adhere to this rule, the behavior of the Provider and the underlying Transport is not defined. Providers that allow Consumers to get ownership of the
local_iov but not the memory it specified back after the
dat_ep_post_recv() returns should document this behavior and also specify its support in Provider attributes. This behavior allows Consumer full control of the
local_iov content after
dat_ep_post_recv() returns. Because this behavior is not guaranteed by all Providers, portable Consumers should not rely on this behavior. Consumers should not rely on the Provider copying
local_iov information.
The
DAT_SUCCESS return of the
dat_ep_post_recv() is at least the equivalent of posting a Receive operation directly by native Transport. Providers should avoid resource allocation as part of
dat_ep_post_recv() to ensure that this operation is nonblocking and thread safe for an UpCall.
If the size of an incoming message is larger than the size of the
local_iov, the reported status of the posted Receive DTO in the corresponding Completion DTO event is
DAT_DTO_LENGTH_ERROR. If the reported status of the Completion DTO event corresponding to the posted Receive DTO is not
DAT_DTO_SUCCESS, the content of the
local_iov is not defined.
The operation is valid for all states of the Endpoint. The actual data transfer does not take place until the Endpoint is in the
DAT_EP_STATE_CONNECTED state. The operation on the Endpoint in
DAT_EP_STATE_DISCONNECTED is allowed. If the operation returns successfully, the posted Recv is immediately flushed to
recv_evd_handle.
RETURN VALUES
DAT_SUCCESS
The operation was successful.
DAT_INSUFFICIENT_RESOURCES
The operation failed due to resource limitations.
DAT_INVALID_PARAMETER
Invalid parameter. For example, one of the IOV segments pointed to a memory outside its LMR.
DAT_INVALID_HANDLE
The ep_handle parameter is invalid.
DAT_PROTECTION_VIOLATION
Protection violation for local or remote memory access. Protection Zone mismatch between an LMR of one of the local_iov segments and the local Endpoint.
DAT_PRIVILEGES_VIOLATION
Privileges violation for local or remote memory access. One of the LMRs used in local_iov was either invalid or did not have the local read privileges.