T_EXDATA_REQ(D7tpi)
T_EXDATA_REQ --
Expedited Data Request
Synopsis
This message consists of one M_PROTO message block
followed by one or more M_DATA message blocks
containing at least one byte of data.
The format of the M_PROTO message block is as follows:
struct T_exdata_req {
long PRIM_type; /* always T_EXDATA_REQ */
long MORE_flag; /* indicates more data in ETSDU */
}
Description
This primitive indicates to the transport provider that this message
contains an expedited transport interface data unit.
One or more expedited transport interface data units form an
expedited transport
service data unit.
-
Note that
the maximum size of a expedited transport service data unit is
indicated to the transport user via the
T_INFO_ACK
primitive.
This primitive has a mechanism which indicates the beginning and end of
an expedited transport service data unit.
However, not all transport providers support the concept of an
expedited transport service data unit.
Parameters
PRIM_type-
identifies the primitive type.
MORE_flag-
when greater than zero indicates that the
next
T_EXDATA_REQ
primitive is also part of this expedited transport service data
unit.
Rules
This primitive does not require any acknowledgments, although
it may generate a fatal error.
This is indicated via a
M_ERROR
message
type which results in the failure of all
operating system service routines on the
stream.
Errors
The allowable errors are as follows:
EPROTO-
This indicates one of the following unrecoverable protocol conditions:
-
The transport service
interface was found to be in an incorrect state.
If the interface is in the
T_IDLE
state when the provider receives
the
T_EXDATA_REQ
primitive, then the transport provider should just
drop the message without generating a fatal error.
-
The amount of transport user data associated with the primitive
defines an expedited transport service data unit larger than that allowed by the
transport provider.
Modes
Only connection-mode.
Originator
Transport user.
Notices
Hardware constraints
None
Applicability
N/A
Backward compatibility
UnixWare-specific TPI Message Formats
Forward compatibility
N/A
19 June 2005
© 2005 The SCO Group, Inc. All rights reserved.
OpenServer 6 and UnixWare (SVR5) HDK - June 2005