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Updated: Thursday, June 13, 2019
 
 

tt_pattern_callback_add (3)

Name

tt_pattern_callback_add - matching callback function

Synopsis

#include <Tt/tt_c.h>
Tt_status tt_pattern_callback_add(Tt_pattern m,
Tt_message_callback f);

Description

ToolTalk Functions                                  tt_pattern_callback_add(3)



NAME
       tt_pattern_callback_add - register a message-matching callback function

SYNOPSIS
       #include <Tt/tt_c.h>
       Tt_status tt_pattern_callback_add(Tt_pattern m,
                                         Tt_message_callback f);

DESCRIPTION
       The  tt_pattern_callback_add()  function  registers a callback function
       that will be automatically invoked by tt_message_receive(3) whenever  a
       message matches the pattern.

       The  callback  is  defined  in  <Tt/tt_c.h>.   If  the callback returns
       TT_CALLBACK_CONTINUE, other callbacks  will  be  run;  if  no  callback
       returns  TT_CALLBACK_PROCESSED,  tt_message_receive(3) returns the mes-
       sage.  If the callback returns TT_CALLBACK_PROCESSED, no further  call-
       backs  will  be  invoked for this event; tt_message_receive(3) does not
       return the message.

       The m argument is the opaque handle for the pattern  involved  in  this
       operation.

       The f argument is the message callback to be run.

       The   application   should  check  the  tt_message_uid(3)  and  tt_mes-
       sage_gid(3) against the User ID and Group ID of the application receiv-
       ing the messsage. If the UID and/or GID of the application do not match
       that of the message then  the  receiving  application  should  consider
       failing the message with TT_DESKTOP_EACCES.

RETURN VALUE
       Upon  successful  completion,  the  tt_pattern_callback_add()  function
       returns the status of the operation as one of the  following  Tt_status
       values:

          TT_OK   The operation completed successfully.

          TT_ERR_NOMP
                  The  ttsession(1)  process  is  not running and the ToolTalk
                  service cannot restart it.

          TT_ERR_POINTER
                  The pointer passed does not point to an object of  the  cor-
                  rect type for this operation.

ATTRIBUTES
       See attributes(7) for descriptions of the following attributes:


       +---------------+------------------+
       |ATTRIBUTE TYPE | ATTRIBUTE VALUE  |
       +---------------+------------------+
       |Availability   | library/tooltalk |
       +---------------+------------------+
       |Stability      | Committed        |
       +---------------+------------------+
SEE ALSO
       tt_c(5), tt_pattern_register(3), tt_message_receive(3).




ToolTalk 1.3                     1 March 1996
                                                    tt_pattern_callback_add(3)