t_listen() — Listen for a connect indication

Standards

Standards / Extensions C or C++ Dependencies
XPG4.2 both  

Format

#define _XOPEN_SOURCE_EXTENDED 1
#include <xti.h>

int t_listen(int fd, struct t_call *call);

General description

Listens for a connect request from a calling transport user. The argument fd identifies the local transport endpoint where connect indications arrive, and on return, call contains information describing the connect 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_connect(). However, t_connect() may fail for other reasons; For example TADDRBUSY. opt returns options associated with the connect request. udata is meaningless because transmission of user data is not supported across a connect request. sequence is a number that uniquely identifies the returned connect indication. The value of sequence enables the user to listen for multiple connect 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_listen() to indicate the maximum size of the buffer for each.

By default, t_listen() executes in synchronous mode and waits for a connect indication to arrive before returning to the user. However, if O_NONBLOCK is set using t_open() or fcntl(), t_listen() executes asynchronously, reducing to a poll for existing connect indications. If none are available, it returns -1 and sets t_errno to TNODATA.

Valid states: T_IDLE, T_INCON

Returned value

If successful, t_listen() returns 0. The TCP transport provider does not differentiate between a connect indication and the connection itself. A successful return of t_listen() indicates an existing connection.

If unsuccessful, t_listen() returns -1 and sets errno to one of the following values:
Error Code
Description
TBADF
The specified file descriptor does not refer to a transport 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 connect indication information to be returned in call is discarded. The value of sequence returned can be used to do a t_snddis() .
TLOOK
An asynchronous event has occurred on this transport endpoint and requires immediate attention.
TNODATA
O_NONBLOCK was set, but no connect indications had been queued.
TNOTSUPPORT
This function is not supported by the underlying transport provider.
TOUTSTATE
The function was issued in the wrong sequence on the transport endpoint referenced by fd.
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 (t_errno).
TQFULL
The maximum number of outstanding indications has been reached for the endpoint referenced by fd.
TSYSERR
A system error has occurred during execution of this function.

Related information

Parent topic: Library functions