Quick Navigator

Search Site

Unix VPS
A - Starter
B - Basic
C - Preferred
D - Commercial
MPS - Dedicated
Previous VPSs
* Sign Up! *

Contact Us
Online Help
Domain Status
Man Pages

Virtual Servers

Topology Map

Server Agreement
Year 2038

USA Flag



Man Pages
update(n) Tcl Built-In Commands update(n)

update - Process pending events and idle callbacks

update ?idletasks?


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.

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 }

after(n), interp(n)

event, flush, handler, idle, update
7.5 Tcl

Search for    or go to Top of page |  Section n |  Main Index

Powered by GSP Visit the GSP FreeBSD Man Page Interface.
Output converted with ManDoc.