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  man pages->Tru64 Unix man pages -> t_look (3)              



NAME    [Toc]    [Back]

       t_look  -  Look  at  the current event on a transport endpoint.

SYNOPSIS    [Toc]    [Back]

       #include <xti.h>

       int t_look(
               int fd );

LIBRARY    [Toc]    [Back]

       XTI Library (libxti.a)

STANDARDS    [Toc]    [Back]

       Interfaces documented on this reference  page  conform  to
       industry standards as follows:

       t_look():  XNS4.0, XNS5.0

       Refer to the standards(5) reference page for more information
 about industry standards and associated tags.

PARAMETERS    [Toc]    [Back]

       The following table summarizes the  relevance  of  the  fd
       parameter when t_look() is called:

       Parameter   Before Call   After Call
       fd          y             n

       Notes  to  Table  This is a meaningful parameter.  This is
       not a meaningful parameter.  Specifies a  file  descriptor
       returned  by  the  t_open()  function  that identifies the
       local transport endpoint.

DESCRIPTION    [Toc]    [Back]

       The t_look() XTI function is used  in  connectionless  and
       connection-oriented  transport service to monitor the current
 event at the transport endpoint specified by  a  file
       descriptor  previously  returned by the t_open() function.
       The t_look() function  permits  a  transport  provider  to
       notify  a  transport  user  of  any  one of the nine asynchronous
 events listed in the RETURN  VALUE  section  when
       the  transport user is calling other XTI functions in synchronous

       During synchronous operation, all events  at  a  transport
       endpoint are saved by XTI so that any current event may be
       known to a transport user. Each of the  nine  asynchronous
       events listed under the RETURN VALUE section is defined by
       a symbolic name in the xti.h include file.  This  symbolic
       name  can  be  retrieved  when  the  t_look()  function is

       Some XTI functions  fail  unconditionally  when  they  are
       called because the current event at the transport endpoint
       does not permit them to successfully execute. Four of  the
       nine  synchronous events listed in the Event column of the
       following table cause unconditional failure when any function
  listed  in  the Immediate T_LOOK Functions column is
       called. Any of these four synchronous events requires that
       the  transport user be immediately notified. Unconditional
       failure returns a [T_LOOK] error during execution  of  the
       currently called function or the next called function when
       it is executed.  This function can then be used to  determine
 which event occurred.

       Event          Immediate  T_LOOK Func-   Event Description
       T_LISTEN       t_accept(),      t_con-   Connection   indication
                      nect()*, t_unbind()       received
       T_DISCONNECT   t_accept(),      t_con-   Disconnect received
                      nect(),   t_listen()**,
                      t_rcv(),      t_rcvconnect(),
                      t_snd(), t_sndrel()
       T_UDERR        t_rcvudata(),   t_sndu-   Datagram  error indicadata()
       T_ORDREL       t_rcvudata(),   t_sndu-   Orderly release indicadata()

       Notes to Table Connection indication received at a  transport
  endpoint  which  has been bound with qlen > 0 (zero)
       and for which a connection indication is pending (refer to
       the  t_bind()  function).   Disconnect  for an outstanding
       connect indication.

       When multiple events occur, the order in which their value
       is  returned  is  implementation  dependent. All together,
       there are 11 XTI functions that  fail  when  a  particular
       synchronous  event  requiring  immediate  notification  is

       The following table lists transport  endpoint  events  and
       corresponding functions to which a [T_LOOK] error is immediately
 returned when the event causes function failure:

       Event          Cleared with T_LOOK?   Event  Consuming   Functions

       T_LISTEN       No                     t_listen()
       T_CONNECT      No                     t_rcvconnect()
       T_DATA         No                     t_rcv(), t_rcvudata()
       T_EXDATA       No                     t_rcv()
       T_DISCONNECT   No                     t_rcvdis()
       T_UDERR        No                     t_rcvuderr()
       T_ORDREL       No                     t_rcvrel()
       T_GODATA       Yes                    t_snd(), t_sndudata()
       T_GOEXDATA     Yes                    t_snd()

       An event at a transport endpoint remains outstanding until
       a consuming function clears it. Every event has an associated
  consuming function that handles the event and clears
       it. The Event Consuming Function column of  the  preceding
       table lists these events and the function that clears each
       one when successfully executed.

RETURN VALUES    [Toc]    [Back]

       Upon successful completion, the t_look() function  returns
       a  value  that indicates which of the allowable events has
       occurred, or returns zero if no event exists. One  of  the
       following events is returned: Connect indication received.
       Connect  confirmation  received.   Normal  data  received.
       Expedited  data  received.  Disconnect received.  Datagram
       error indication.  Orderly release indication.  Flow  control
  restrictions  on  normal data flow have been lifted.
       Normal data may be sent again.  Flow control  restrictions
       on  expedited  data  flow have been lifted. Expedited data
       may be sent again.

       Upon failure, the value -1 is returned and t_errno is  set
       to indicate the error.

ERRORS    [Toc]    [Back]

       If  the  t_look() function fails, t_errno is set to one of
       the following values: The specified file  descriptor  does
       not  refer  to  a  transport  endpoint.   A  system  error
       occurred during execution of this  function.   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).

VALID STATES    [Toc]    [Back]

       The  t_look()  function  can  be  called  in all transport
       provider states except T_UNINIT.

SEE ALSO    [Toc]    [Back]

       Functions:    t_bind(3),    t_connect(3),     t_listen(3),
       t_open(3),    t_rcv(3),    t_rcvconnect(3),   t_rcvdis(3),
       t_rcvrel(3),   t_rcvudata(3),   t_rcvuderr(3),   t_snd(3),

       Standards: standards(5)

       Network Programmer's Guide

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 Similar pages
Name OS Title
t_look IRIX look at the current event on a transport endpoint
t_look HP-UX look at the current event on a transport endpoint
t_close IRIX close a transport endpoint
t_close Tru64 Close a transport endpoint.
t_open Tru64 Establishes a transport endpoint
t_open IRIX establish a transport endpoint
t_unbind IRIX disable a transport endpoint
t_unbind Tru64 Disable a transport endpoint.
t_unbind HP-UX disable a transport endpoint
t_open HP-UX establish a transport endpoint
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