DAT_EP_POST_SEND(3DAT) Direct Access Transport Library Functions


NAME


dat_ep_post_send - transfer data to the remote side

SYNOPSIS


cc [ flag... ] file... -ldat [ library... ]
#include <dat/udat.h>

DAT_RETURN
dat_ep_post_send (
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 0
size message.


local_iov
I/O Vector that specifies the local buffer that
contains data to be transferred. Can be NULL for 0
size message.


user_cookie:
User-provided cookie that is returned to the Consumer
at the completion of the send. Can be NULL.


completion_flags
Flags for posted Send. The default
DAT_COMPLETION_DEFAULT_FLAG is 0x00. Other values
are as follows:

Completion Suppression
DAT_COMPLETION_SUPPRESS_FLAG

0x01
Suppress
successful
Completion.


Solicited Wait
DAT_COMPLETION_SOLICITED_WAIT_FLAG

0x02
Request for
notification
completion for
matching
receive on the
other side of
the connection.


Notification of Completion
DAT_COMPLETION_UNSIGNALLED_FLAG

0x04
Non-
notification
completion.
Local Endpoint
must be
configured for
Notification
Suppression.


Barrier Fence
DAT_COMPLETION_BARRIER_FENCE_FLAG

0x08
Request for
Barrier Fence.


DESCRIPTION


The dat_ep_post_send() function requests a transfer of all the data from
the local_iov over the connection of the ep_handle Endpoint to the remote
side.


The num_segments parameter specifies the number of segments in the
local_iov. The local_iov segments are traversed in the I/O Vector order
until all the data is transferred.


A Consumer cannot 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 back after the
dat_ep_post_send() returns should document this behavior and also specify
its support in Provider attributes. This behavior allows Consumers full
control of the local_iov, but not the memory it specifies after
dat_ep_post_send() 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_send() is at least the
equivalent of posting a Send operation directly by native Transport.
Providers should avoid resource allocation as part of dat_ep_post_send()
to ensure that this operation is nonblocking and thread safe for an
UpCall.


The completion of the posted Send is reported to the Consumer
asynchronously through a DTO Completion event based on the specified
completion_flags value. The value of DAT_COMPLETION _UNSIGNALLED_FLAG is
only valid if the Endpoint Request Completion Flags
DAT_COMPLETION_UNSIGNALLED_FLAG. Otherwise, DAT_INVALID_PARAMETER is
returned.


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 Send.


The operation is valid for the Endpoint in the DAT_EP_STATE_CONNECTED and
DAT_EP_STATE_DISCONNECTED states. If the operation returns successfully
for the Endpoint in the DAT_EP_STATE_DISCONNECTED state, the posted Send
is immediately flushed to request_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_INVALID_STATE
A parameter is in an invalid state.
Endpoint was not in the
DAT_EP_STATE_CONNECTED or
DAT_EP_STATE_DISCONNECTED state.


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.


USAGE


For best Send operation performance, the Consumer should align each
buffer segment of local_iov to the Optimal Buffer Alignment attribute of
the Provider. For portable applications, the Consumer should align each
buffer segment of local_iov to the DAT_OPTIMAL_ALIGNMENT.

ATTRIBUTES


See attributes(5) for descriptions of the following attributes:


+--------------------+---------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+---------------------------+
|Interface Stability | Standard: uDAPL, 1.1, 1.2 |
+--------------------+---------------------------+
|MT-Level | Unsafe |
+--------------------+---------------------------+

SEE ALSO


libdat(3LIB), attributes(5)


July 16, 2004 DAT_EP_POST_SEND(3DAT)