dat_ep_post_recv(3DDirect Access Transport Library Functdat_ep_post_recv(3DAT)NAMEdat_ep_post_recv - receive data over the connection of the Endpoint
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 Con‐
sumer at the completion of the Receive DTO. Can be
NULL.
completion_flags Flags for posted Receive. The default DAT_COMPLE‐
TION_DEFAULT_FLAG is 0x00. Other values are as fol‐
lows:
Notification of Completion DAT_COMPLE‐
TION_UNSIGNALLED_FLAG
0x04 Non-notifica‐
tion comple‐
tion. Local
Endpoint must
be configured
for
Unsignaled
CompletionNo‐
tification
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 asyn‐
chronously 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 behav‐
ior 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 shouldnot rely on the Provider copying local_iov
information.
The DAT_SUCCESS return of the dat_ep_post_recv() is at least the equiv‐
alent 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 corre‐
sponding 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 success‐
fully, 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 lim‐
itations.
DAT_INVALID_PARAMETER Invalid parameter. For example, one of
the IOV segments pointed to a memory out‐
side 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.
USAGE
For best Recv 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 │Committed │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │Unsafe │
├─────────────────────────────┼─────────────────────────────┤
│Standard │uDAPL, 1.1, 1.2 │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOlibdat(3LIB), attributes(5)SunOS 5.11 16 Jul 2004 dat_ep_post_recv(3DAT)
