T_UNITDATA_REQ(D7tpi)
T_UNITDATA_REQ --
Unitdata Request
Synopsis
This message consists of one M_PROTO message block
followed by zero or more M_DATA message blocks
where each M_DATA message block contains zero or more bytes of data.
The format of the M_PROTO message block is as follows:
struct T_unitdata_req {
long PRIM_type; /* always T_UNITDATA_REQ */
long DEST_length; /* dest addr length */
long DEST_offset; /* dest addr offset */
long OPT_length; /* options length */
long OPT_offset; /* options offset */
}
Description
This primitive requests that the transport provider send the specified
datagram
to the specified destination.
Parameters
PRIM_type-
identifies the primitive type.
DEST_length-
is the length of the destination address
DEST_offset-
is the offset
(from the beginning of the M_PROTO message block)
where the destination address begins.
OPT_length-
is the length
of the requested options associated with the primitive.
OPT_offset-
is the offset
(from the beginning of the M_PROTO message block)
of the requested options associated with the primitive.
The proper alignment of the destination address and options in the
M_PROTO message block is not guaranteed.
The destination address and options in the
M_PROTO message block are, however, aligned the same as they
were received from the transport user.
This primitive does not require any acknowledgment.
If a non-fatal error occurs, it is the responsibility
of the transport provider to report it via the
T_UDERROR_IND
indication.
Fatal errors are indicated via a
M_ERROR
message type which results in the failure of
all operating system service routines on the
stream.
Errors
The allowable fatal 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.
-
The amount of transport user data associated with the primitive
defines an transport service data unit larger than that allowed by the
transport provider.
Modes
Only connectionless-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