Manual Pages for UNIX Operating System command usage for man update

Tcl Built-In Commands                                  update(1T)



_________________________________________________________________

NAME
     update - Process pending events and idle callbacks

SYNOPSIS
     update ?idletasks?
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DESCRIPTION
     This command is used to bring the application ``up to date''
     by  entering  the  event  loop  repeatedly until all pending
     events (including idle callbacks) have been processed.

     If the idletasks keyword is specified as an argument to  the
     command,  then  no new events or errors are processed;  only
     idle callbacks are invoked.  This causes operations that are
     normally deferred, such as display updates and window layout
     calculations, to be performed immediately.

     The update idletasks command  is  useful  in  scripts  where
     changes  have  been  made to the application's state and you
     want those changes to appear  on  the  display  immediately,
     rather  than  waiting  for  the  script  to  complete.  Most
     display updates are performed as idle callbacks,  so  update
     idletasks  will  cause them to run.  However, there are some
     kinds of updates that only happen  in  response  to  events,
     such  as  those  triggered  by  window  size  changes; these
     updates will not occur in update idletasks.

     The update command with no  options  is  useful  in  scripts
     where  you are performing a long-running computation but you
     still want the application to respond to events such as user
     interactions;   if  you  occasionally  call update then user
     input will be processed during the next call to update.

EXAMPLE
     Run computations for about a second and then finish:
          set x 1000
          set done 0
          after 1000 set done 1
          while {!$done} {
              # A very silly example!
              set x [expr {log($x) ** 2.8}]

              # Test to see if our time-limit has been hit.  This would
              # also give a chance for serving network sockets and, if
              # the Tk package is loaded, updating a user interface.
              update
          }




Tcl                     Last change: 7.5                        1






Tcl Built-In Commands                                  update(1T)



SEE ALSO
     after(1T), bgerror(1T)


KEYWORDS
     event, flush, handler, idle, update

ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:

     _______________________________________
    |   ATTRIBUTE TYPE   |  ATTRIBUTE VALUE|
    |____________________|__________________|_
    | Availability       |  runtime/tcl-8  |
    |____________________|__________________|_
    | Interface Stability|  Uncommitted    |
    |____________________|_________________|

NOTES
     Source for Tcl is available on http://opensolaris.org.


































Tcl                     Last change: 7.5                        2