Networking Services Library Functions tsndvudata(3NSL)
NAME
tsndvudata - send a data unit from one or more noncontigu-
ous buffers
SYNOPSIS
#include
int tsndvudata(int fd, struct tunitdata *unitdata, struct tiovec *iov,
unsigned int iovcount);
DESCRIPTION
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, iovcount contains the number of non-contiguous udata
buffers and is limited to an implementation-defined value
given by TIOVMAX which is at least 16, and unitdata
points to a tunitdata structure containing the following
members:
struct netbuf addr;
struct netbuf opt;
struct netbuf udata;
If the limit on iovcount is exceeded, the function fails
with TBADATA.
In unitdata, addr specifies the protocol address of the
destination user, and opt identifies options that the user
wants associated with this request. The udata field is not
used. 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 may use
default options.
The data to be sent is identified by iov[0] through iov
[iovcount-1].
Note that the limit on the total number of bytes available
in all buffers passed:
iov(0).iovlen ] . . ] iov(iovcount-1).iovlen
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Networking Services Library Functions tsndvudata(3NSL)
may be constrained by implementation limits. If no other
constraint applies, it will be limited by INTMAX. In prac-
tice, the availability of memory to an application is likely
to impose a lower limit on the amount of data that can be
sent or received using scatter/gather functions.
By default, tsndvudata() operates in synchronous mode and
may wait if flow control restrictions prevent the data from
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), tsndvudata() executes 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 iov0 through iov
[iovcount-1] exceeds the TSDU size as returned in the tsdu
field of the info argument of topen(3NSL) or
tgetinfo(3NSL), or is zero and sending of zero octets is
not supported by the underlying transport service, a TBAD-
DATA error is generated. If tsndvudata() 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(3NSL). An application must therefore be prepared
to receive these errors in both of these ways.
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.
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Networking Services Library Functions tsndvudata(3NSL)
o A single send was attempted specify-
ing a TSDU greater than that speci-
fied in the info argument, or a send
of a zero byte TSDU is not supported
by the provider.
o iovcount is greater than TIOVMAX.
TBADF The specified file descriptor does not refer
to a transport endpoint.
TBADOPT The specified options were in an incorrect
format or contained illegal information.
TFLOW ONONBLOCK i 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
In the TLI interface definition, no counterpart of this rou-
tine was defined.
ATRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
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Networking Services Library Functions tsndvudata(3NSL)
ATRIBUTE TYPE ATRIBUTE VALUE
MT Level Safe
SEE ALSO
fcntl(2), talloc(3NSL), topen(3NSL), trcvudata(3NSL),
trcvvudata(3NSL) trcvuderr(3NSL), tsndudata(3NSL), attri-
butes(5)
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