# uevent::onidle(3tcl) 0.2 uev "User events"

## Name

uevent::onidle - Request merging and deferal to idle time

## Synopsis

- package require Tcl 8.5 9
- package require uevent::onidle ?0.2?
- package require logger

- ::uevent::onidle objectName commandprefix
- objectName request

## Description

This package provides objects which can merge multiple requestes for an action and execute the action the moment the system (event loop) becomes idle. The action to be run is configured during object construction.

## API

The package exports a class, uevent::onidle, as specified below.

::uevent::onidle objectName commandprefix

  The command creates a new onidle object with an associated global Tcl command whose name is objectName. This command may be used to invoke various operations on the object.

  The commandprefix is the action to perform when the event loop is idle and the user asked for it using the method request (See below).

The object commands created by the class commands above have the form:

objectName request

  This method requests the execution of the command prefix specified during the construction of objectName the next time the event loop is idle. Multiple requests are merged and cause only one execution of the command prefix.

## Examples

Examples of this type of deferal are buried in the (C-level) implementations all the Tk widgets, defering geometry calculations and window redraw activity in this manner.

## Bugs, Ideas, Feedback

This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category uevent of the Tcllib Trackers. Please also report any ideas for enhancements you may have for either package and/or documentation.

When proposing code changes, please provide unified diffs, i.e the output of diff -u.

Note further that attachments are strongly preferred over inlined patches. Attachments can be made by going to the Edit form of the ticket immediately after its creation, and then using the left-most button in the secondary navigation bar.

## Keywords

callback, deferal, event, idle, merge, on-idle

## Copyright

Copyright © 2008 Andreas Kupries <andreas_kupries@users.sourceforge.net>