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			76 lines
		
	
	
		
			3.0 KiB
		
	
	
	
		
			HTML
		
	
	
	
	
	
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|  | 	<title>Logtalk built-in predicate: threaded_once/1-2</title> | ||
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|  | <div class="top-left">Logtalk reference manual</div>  | ||
|  | <div class="top-right">Built-in predicate: threaded_once/1-2</div> | ||
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|  | <div class="navtop"><a href="../../index.html">contents</a> > <a href="../index.html">reference manual</a> > <a href="../index.html#builtins">built-in predicates</a></div> | ||
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|  | <h2 id="builtins_threaded_once1_2" class="codenp">threaded_once/1-2</h2> | ||
|  | 
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|  | <h4>Description</h4> | ||
|  | 
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|  | <pre>threaded_once(Goal) | ||
|  | threaded_once(Goal, Tag)</pre> | ||
|  | <p> | ||
|  | Proves <code>Goal</code> asynchronously using a new thread. Only the first goal solution is found. The argument can be a message sending goal. This call always succeeds. The result (success, failure, or exception) is sent back to the message queue of the object containing the call (<em>this</em>). | ||
|  | </p> | ||
|  | <p> | ||
|  | The variant <code>threaded_once/2</code> returns a threaded call identifier tag that can be used with the <a title="Consult reference manual" href="threaded_exit1_2.html"><code>threaded_exit/2</code></a> predicate. Tags shall be considered as an opaque term; users shall not rely on its type. | ||
|  | </p> | ||
|  | 
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|  | <h4>Template and modes</h4> | ||
|  | 
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|  | <pre>threaded_once(@callable) | ||
|  | threaded_once(@callable, -nonvar)</pre> | ||
|  | 
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|  | <h4>Errors</h4> | ||
|  | 
 | ||
|  | <dl> | ||
|  | 	<dt>Goal is a variable:</dt> | ||
|  | 		<dd><code>instantiation_error</code></dd> | ||
|  | 	<dt>Goal is neither a variable nor a callable term:</dt> | ||
|  | 		<dd><code>type_error(callable, Goal)</code></dd> | ||
|  | 	<dt>Tag is not a variable:</dt> | ||
|  | 		<dd><code>type_error(variable, Goal)</code></dd> | ||
|  | </dl> | ||
|  | 
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|  | <h4>Examples</h4> | ||
|  | 
 | ||
|  | <dl> | ||
|  | 	<dt>Prove <code>Goal</code> asynchronously in a new thread:</dt> | ||
|  | 		<dd><code>threaded_once(Goal)</code></dd> | ||
|  | 	<dt>Prove <code>::Message</code> asynchronously in a new thread:</dt> | ||
|  | 		<dd><code>threaded_once(::Message)</code></dd> | ||
|  | 	<dt>Prove <code>Object::Message</code> asynchronously in a new thread:</dt> | ||
|  | 		<dd><code>threaded_once(Object::Message)</code></dd> | ||
|  | </dl> | ||
|  | 
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|  | 		<span>Copyright © <a href="mailto:pmoura@logtalk.org">Paulo Moura</a> — <a href="http://logtalk.org">Logtalk.org</a></span><br/>	 | ||
|  | 		<span>Last updated on: September 15, 2007</span> | ||
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