t_listen(3NSL) Networking Services Library Functions t_listen(3NSL)NAMEt_listen - listen for a connection indication
SYNOPSIS
#include <xti.h>
int t_listen(int fd, struct t_call *call);
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 listens for a connection indication from a calling trans‐
port user. The argument fd identifies the local transport endpoint
where connection indications arrive, and on return, call contains
information describing the connection indication. The parameter call
points to a t_call structure which contains the following members:
struct netbuf addr;
struct netbuf opt;
struct netbuf udata;
int sequence;
In call, addr returns the protocol address of the calling transport
user. This address is in a format usable in future calls to t_con‐
nect(3NSL). Note, however that t_connect(3NSL) may fail for other rea‐
sons, for example TADDRBUSY. opt returns options associated with the
connection indication, udata returns any user data sent by the caller
on the connection request, and sequence is a number that uniquely iden‐
tifies the returned connection indication. The value of sequence
enables the user to listen for multiple connection indications before
responding to any of them.
Since this function returns values for the addr, opt and udata fields
of call, the maxlen field of each must be set before issuing the t_lis‐
ten() to indicate the maximum size of the buffer for each. If the
maxlen field of call→addr, call→opt or call→udata is set to zero, no
information is returned for this parameter.
By default, t_listen() executes in synchronous mode and waits for a
connection indication to arrive before returning to the user. However,
if O_NONBLOCK is set via t_open(3NSL) or fcntl(2), t_listen() executes
asynchronously, reducing to a poll for existing connection indications.
If none are available, it returns -1 and sets t_errno to TNODATA.
RETURN VALUES
Upon successful completion, a value of 0 is returned. Otherwise, a
value of −1 is returned and t_errno is set to indicate an error.
VALID STATES
T_IDLE, T_INCON
ERRORS
On failure, t_errno is set to one of the following:
TBADF The specified file descriptor does not refer to a trans‐
port endpoint.
TBADQLEN The argument qlen of the endpoint referenced by fd is
zero.
TBUFOVFLW The number of bytes allocated for an incoming argument
(maxlen) is greater than 0 but not sufficient to store
the value of that argument. The provider's state, as
seen by the user, changes to T_INCON, and the connection
indication information to be returned in call is dis‐
carded. The value of sequence returned can be used to do
a t_snddis(3NSL).
TLOOK An asynchronous event has occurred on this transport
endpoint and requires immediate attention.
TNODATA O_NONBLOCK was set, but no connection indications had
been queued.
TNOTSUPPORT This function is not supported by the underlying trans‐
port 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 (t_errno).
TQFULL The maximum number of outstanding connection indica‐
tions has been reached for the endpoint referenced by
fd. Note that a subsequent call to t_listen() may block
until another incoming connection indication is avail‐
able. This can only occur if at least one of the out‐
standing connection indications becomes no longer out‐
standing, for example through a call to t_accept(3NSL).
TSYSERR A system error has occurred during execution of this
function.
TLI COMPATIBILITY
The XTI and TLI interface definitions have common names but use differ‐
ent header files. This, and other semantic differences between the two
interfaces are described in the subsections below.
Interface Header
The XTI interfaces use the header file, xti.h. TLI interfaces should
not use this header. They should use the header:
#include <tiuser.h>
Error Description Values
The t_errno values TPROT0, TBADQLEN, and TQFULL can be set by the XTI
interface but not by the TLI interface.
A t_errno value that this routine can return under different circum‐
stances than its XTI counterpart is TBUFOVFLW. It can be returned even
when the maxlen field of the corresponding buffer has been set to zero.
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.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│MT Level │Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOfcntl(2), t_accept(3NSL), t_alloc(3NSL), t_bind(3NSL), t_connect(3NSL),
t_open(3NSL), t_optmgmt(3NSL), t_rcvconnect(3NSL), t_snddis(3NSL),
attributes(5)WARNINGS
Some transport providers do not differentiate between a connection
indication and the connection itself. If this is the case, a successful
return of t_listen() indicates an existing connection.
SunOS 5.10 7 May 1998 t_listen(3NSL)
