EVOLUTION-MANAGER

Edit File: taskCallbackNames.html

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<table width="100%" summary="page for taskCallbackNames {base}"><tr><td>taskCallbackNames {base}</td><td style="text-align: right;">R Documentation</td></tr></table>

<h2>Query the Names of the Current Internal Top-Level Task Callbacks</h2>

<h3>Description</h3>

<p>This provides a way to get the names (or identifiers)
for the currently registered task callbacks
that are invoked at the conclusion of each top-level task.
These identifiers can be used to remove a callback.
</p>

<h3>Usage</h3>

<pre>
getTaskCallbackNames()
</pre>

<h3>Value</h3>

<p>A character vector giving the name for each of the
registered callbacks which are invoked when
a top-level task is completed successfully.
Each name is the one used when registering
the callbacks and returned as the in the
call to <code><a href="taskCallback.html">addTaskCallback</a></code>.
</p>

<p>One can use <code><a href="taskCallbackManager.html">taskCallbackManager</a></code>
to manage user-level task callbacks,
i.e., S-language functions, entirely within
the S language and access the names
more directly.
</p>

<p><code><a href="taskCallback.html">addTaskCallback</a></code>,
<code><a href="taskCallback.html">removeTaskCallback</a></code>,
<code><a href="taskCallbackManager.html">taskCallbackManager</a></code>\
<a href="https://developer.r-project.org/TaskHandlers.pdf">https://developer.r-project.org/TaskHandlers.pdf</a>
</p>

<h3>Examples</h3>

<pre>
 n &lt;- addTaskCallback(function(expr, value, ok, visible) {
                        cat("In handler\n")
                        return(TRUE)
                      }, name = "simpleHandler")

getTaskCallbackNames()

# now remove it by name
 removeTaskCallback("simpleHandler")

h &lt;- taskCallbackManager()
 h$add(function(expr, value, ok, visible) {
                        cat("In handler\n")
                        return(TRUE)
                      }, name = "simpleHandler")
 getTaskCallbackNames()
 removeTaskCallback("R-taskCallbackManager")
</pre>

<hr /><div style="text-align: center;">[Package <em>base</em> version 3.6.0 <a href="00Index.html">Index</a>]</div>
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