Networking Services Library Functions tsndudata(3NSL)
NAME
tsndudata - send a data unit
SYNOPSIS
#include
int tsndudata(int fd, const struct tunitdata *unitdata);
DESCRIPTION
This routine is part of the XTI interfaces which evolved
from the TLI interfaces. XTI represents the future evolution
of these interfaces. However, TLI interfaces are supported
for compatibility. When using a TLI routine that has the
same name as an XTI routine, the tiuser.h header file must
be used. Refer to the TLI COMPATIBILITY section for a
description of differences between the two interfaces.
This function is used in connectionless-mode to send a data
unit to another transport user. The argument fd identifies
the local transport endpoint through which data will be
sent, and unitdata points to a tunitdata structure contain-
ing the following members:
struct netbuf addr;
struct netbuf opt;
struct netbuf udata;
In unitdata, addr specifies the protocol address of the des-
tination user, opt identifies options that the user wants
associated with this request, and udata specifies the user
data to be sent. The user may choose not to specify what
protocol options are associated with the transfer by setting
the len field of opt to zero. In this case, the provider
uses the option values currently set for the communications
endpoint.
If the len field of udata is zero, and sending of zero
octets is not supported by the underlying transport service,
the tsndudata() will return -1 with terrno set to TBAD-
DATA.
By default, tsndudata() operates in synchronous mode and
may wait if flow control restrictions prevent the data from
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Networking Services Library Functions tsndudata(3NSL)
being accepted by the local transport provider at the time
the call is made. However, if ONONBLOCK is set by means
of topen(3NSL) or fcntl(2), tsndudata() will execute in
asynchronous mode and will fail under such conditions. The
process can arrange to be notified of the clearance of a
flow control restriction by means of either tlook(3NSL) or
the EM interface.
If the amount of data specified in udata exceeds the TSDU
size as returned in the tsdu field of the info argument of
topen(3NSL) or tgetinfo(3NSL), a TBADATA error will be
generated. If tsndudata() is called before the destination
user has activated its transport endpoint (see
tbind(3NSL)), the data unit may be discarded.
If it is not possible for the transport provider to immedi-
ately detect the conditions that cause the errors TBADADR
and TBADOPT, these errors will alternatively be returned by
trcvuderr. Therefore, an application must be prepared to
receive these errors in both of these ways.
If the call is interrupted, tsndudata() will return EINTR
and the datagram will not be sent.
RETURN VALUES
Upon successful completion, a value of 0 is returned. Oth-
erwise, a value of -1 is returned and terrno is set to
indicate an error.
VALID STATES
TIDLE.
ERORS
On failure, terrno is set to one of the following:
TBADADR The specified protocol address was in an
incorrect format or contained illegal infor-
mation.
TBADATA Illegal amount of data. A single send was
attempted specifying a TSDU greater than that
specified in the info argument, or a send of
a zero byte TSDU is not supported by the pro-
vider.
TBADF The specified file descriptor does not refer
to a transport endpoint.
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Networking Services Library Functions tsndudata(3NSL)
TBADOPT The specified options were in an incorrect
format or contained illegal information.
TFLOW ONONBLOCK was set, but the flow control
mechanism prevented the transport provider
from accepting any data at this time.
TLOK An asynchronous event has occurred on this
transport endpoint.
TNOTSUPORT This function is not supported by the under-
lying transport provider.
TOUTSTATE The communications endpoint referenced by fd
is not in one of the states in which a call
to this function is valid.
TPROTO This error indicates that a communication
problem has been detected between XTI and the
transport provider for which there is no
other suitable XTI error (terrno).
TSYSER A system error has occurred during execution
of this function.
TLI COMPATIBILITY
The XTI and TLI interface definitions have common names but
use different header files. This, and other semantic differ-
ences between the two interfaces are described in the sub-
sections below.
Interface Header
The XTI interfaces use the header file, xti.h. TLI inter-
faces should not use this header. They should use the
header:
#include
Error Description Values
The terrno values that can be set by the XTI interface and
cannot be set by the TLI interface are:
TPROTO
TBADADR
TBADOPT
TLOK
TOUTSTATE
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Networking Services Library Functions tsndudata(3NSL)
Notes
Whenever this function fails with terror set to TFLOW,
ONONBLOCK must have been set.
Option Buffers
The format of the options in an opt buffer is dictated by
the transport provider. Unlike the XTI interface, the TLI
interface does not fix the buffer format.
ATRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
ATRIBUTE TYPE ATRIBUTE VALUE
MT Level Safe
SEE ALSO
fcntl(2), talloc(3NSL), tbind(3NSL), terror(3NSL),
tgetinfo(3NSL), tlook(3NSL), topen(3NSL),
trcvudata(3NSL), trcvuderr(3NSL), attributes(5)
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