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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Class Poco::ClassLoader</title>
<meta http-equiv="content-type" content="text/html; charset=utf-8"/>
<meta name="author" content="Applied Informatics Software Engineering GmbH and Contributors"/>
<meta name="publisher" content="Applied Informatics Software Engineering GmbH and Contributors"/>
<meta name="copyright" content="Copyright (c) 2009, Applied Informatics Software Engineering GmbH and Contributors"/>
<meta name="language" content="en"/>
<meta name="date" content="2009-11-24"/>
<meta name="generator" content="PocoDoc"/>
<link rel="stylesheet" href="css/styles.css" type="text/css"/>
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<body bgcolor="#ffffff" leftmargin="0" topmargin="0">
<div class="header">
<h1 class="namespace"><a href="Poco.html" class="namespace">Poco</a></h1>
<h1 class="template">template < class Base ></h1>
<h1 class="symbol">class ClassLoader</h1>
</div>
<div class="body">
<p>
<b>Library:</b> Foundation<br />
<b>Package:</b> SharedLibrary<br />
<b>Header:</b> Poco/ClassLoader.h</p>
<h2>Description</h2>
<div class="description">
<p>The <a href="Poco.ClassLoader.html" title="class Poco::ClassLoader">ClassLoader</a> loads C++ classes from shared libraries at runtime. It must be instantiated with a root class of the loadable classes. For a class to be loadable from a library, the library must provide a <a href="Poco.Manifest.html" title="class Poco::Manifest">Manifest</a> of all the classes it contains. The <a href="Poco.Manifest.html" title="class Poco::Manifest">Manifest</a> for a shared library can be easily built with the help of the macros in the header file "Foundation/ClassLibrary.h". </p>
<p>Starting with POCO release 1.3, a class library can export multiple manifests. In addition to the default (unnamed) manifest, multiple named manifests can be exported, each having a different base class. </p>
<p>There is one important restriction: one instance of <a href="Poco.ClassLoader.html" title="class Poco::ClassLoader">ClassLoader</a> can only load one manifest from a class library. </p>
</div>
<h2>Member Summary</h2>
<p><b>Member Functions: </b><a href="Poco.ClassLoader.html#4239" title="Poco::ClassLoader::begin()">begin</a>, <a href="Poco.ClassLoader.html#4225" title="Poco::ClassLoader::canCreate()">canCreate</a>, <a href="Poco.ClassLoader.html#4219" title="Poco::ClassLoader::classFor()">classFor</a>, <a href="Poco.ClassLoader.html#4221" title="Poco::ClassLoader::create()">create</a>, <a href="Poco.ClassLoader.html#4227" title="Poco::ClassLoader::destroy()">destroy</a>, <a href="Poco.ClassLoader.html#4240" title="Poco::ClassLoader::end()">end</a>, <a href="Poco.ClassLoader.html#4217" title="Poco::ClassLoader::findClass()">findClass</a>, <a href="Poco.ClassLoader.html#4233" title="Poco::ClassLoader::findManifest()">findManifest</a>, <a href="Poco.ClassLoader.html#4223" title="Poco::ClassLoader::instance()">instance</a>, <a href="Poco.ClassLoader.html#4230" title="Poco::ClassLoader::isAutoDelete()">isAutoDelete</a>, <a href="Poco.ClassLoader.html#4237" title="Poco::ClassLoader::isLibraryLoaded()">isLibraryLoaded</a>, <a href="Poco.ClassLoader.html#4210" title="Poco::ClassLoader::loadLibrary()">loadLibrary</a>, <a href="Poco.ClassLoader.html#4235" title="Poco::ClassLoader::manifestFor()">manifestFor</a>, <a href="Poco.ClassLoader.html#4215" title="Poco::ClassLoader::unloadLibrary()">unloadLibrary</a></p>
<h2>Nested Classes</h2>
<h3><a href="Poco.ClassLoader.Iterator.html" class="class">class Iterator</a></h3>
<p> The <a href="Poco.ClassLoader.html" title="class Poco::ClassLoader">ClassLoader</a>'s very own iterator class. <a href="Poco.ClassLoader.Iterator.html"><img src="images/arrow.gif" alt="more..." style="vertical-align:baseline;" border="0" /> </a></p>
<h3><a href="Poco.ClassLoader.LibraryInfo.html" class="class">struct LibraryInfo</a></h3>
<p> <a href="Poco.ClassLoader.LibraryInfo.html"><img src="images/arrow.gif" alt="more..." style="vertical-align:baseline;" border="0" /> </a></p>
<h2>Types</h2>
<h3><a name="4187">LibraryMap</a></h3>
<p class="decl">typedef std::map < std::string, <a href="Poco.ClassLoader.LibraryInfo.html" title="struct Poco::ClassLoader::LibraryInfo">LibraryInfo</a> > <a href="Poco.ClassLoader.html#4187" title="Poco::ClassLoader::LibraryMap">LibraryMap</a>;</p>
<div class="description">
<p></p>
</div>
<h3><a name="4179">Manif</a></h3>
<p class="decl">typedef <a href="Poco.Manifest.html" title="class Poco::Manifest">Manifest</a> < Base > <a href="Poco.ClassLoader.html#4179" title="Poco::ClassLoader::Manif">Manif</a>;</p>
<div class="description">
<p></p>
</div>
<h3><a name="4178">Meta</a></h3>
<p class="decl">typedef <a href="Poco.AbstractMetaObject.html" title="class Poco::AbstractMetaObject">AbstractMetaObject</a> < Base > <a href="Poco.ClassLoader.html#4178" title="Poco::ClassLoader::Meta">Meta</a>;</p>
<div class="description">
<p></p>
</div>
<h3><a name="4182">bool</a></h3>
<p class="decl">typedef bool (* BuildManifestFunc)(<a href="Poco.ManifestBase.html" title="class Poco::ManifestBase">ManifestBase</a> *);</p>
<div class="description">
<p></p>
</div>
<h3><a name="4180">void</a></h3>
<p class="decl">typedef void (* InitializeLibraryFunc)();</p>
<div class="description">
<p></p>
</div>
<h3><a name="4181">void</a></h3>
<p class="decl">typedef void (* UninitializeLibraryFunc)();</p>
<div class="description">
<p></p>
</div>
<h2>Constructors</h2>
<h3><a name="4208">ClassLoader</a> <img src="images/inline.gif" alt="inline" title="inline" style="vertical-align:baseline;" border="0" /> </h3>
<p class="decl"><a href="Poco.ClassLoader.html" title="class Poco::ClassLoader">ClassLoader</a>();</p>
<div class="description">
<p>Creates the <a href="Poco.ClassLoader.html" title="class Poco::ClassLoader">ClassLoader</a>. </p>
</div>
<h2>Destructor</h2>
<h3><a name="4209">~ClassLoader</a> <img src="images/virtual.gif" alt="virtual" title="virtual" style="vertical-align:baseline;" border="0" /> <img src="images/inline.gif" alt="inline" title="inline" style="vertical-align:baseline;" border="0" /> </h3>
<p class="decl">virtual ~<a href="Poco.ClassLoader.html" title="class Poco::ClassLoader">ClassLoader</a>();</p>
<div class="description">
<p>Destroys the <a href="Poco.ClassLoader.html" title="class Poco::ClassLoader">ClassLoader</a>. </p>
</div>
<h2>Member Functions</h2>
<h3><a name="4239">begin</a> <img src="images/inline.gif" alt="inline" title="inline" style="vertical-align:baseline;" border="0" /> </h3>
<p class="decl"><a href="Poco.ClassLoader.Iterator.html" title="class Poco::ClassLoader::Iterator">Iterator</a> begin() const;</p>
<div class="description">
<p></p>
</div>
<h3><a name="4225">canCreate</a> <img src="images/inline.gif" alt="inline" title="inline" style="vertical-align:baseline;" border="0" /> </h3>
<p class="decl">bool canCreate(<br /> const std::string & className<br />) const;</p>
<div class="description">
<p>Returns true if <a href="Poco.ClassLoader.html#4221" title="Poco::ClassLoader::create()">create</a>() can create new instances of the class. </p>
</div>
<h3><a name="4219">classFor</a> <img src="images/inline.gif" alt="inline" title="inline" style="vertical-align:baseline;" border="0" /> </h3>
<p class="decl">const <a href="Poco.ClassLoader.html#4178" title="Poco::ClassLoader::Meta">Meta</a> & classFor(<br /> const std::string & className<br />) const;</p>
<div class="description">
<p>Returns a reference to the <a href="Poco.MetaObject.html" title="class Poco::MetaObject">MetaObject</a> for the given class. Throws a <a href="Poco.NotFoundException.html" title="class Poco::NotFoundException">NotFoundException</a> if the class is not known. </p>
</div>
<h3><a name="4221">create</a> <img src="images/inline.gif" alt="inline" title="inline" style="vertical-align:baseline;" border="0" /> </h3>
<p class="decl">Base * create(<br /> const std::string & className<br />) const;</p>
<div class="description">
<p>Creates an instance of the given class. Throws a <a href="Poco.NotFoundException.html" title="class Poco::NotFoundException">NotFoundException</a> if the class is not known. </p>
</div>
<h3><a name="4227">destroy</a> <img src="images/inline.gif" alt="inline" title="inline" style="vertical-align:baseline;" border="0" /> </h3>
<p class="decl">void destroy(<br /> const std::string & className,<br /> Base * pObject<br />) const;</p>
<div class="description">
<p>Destroys the object pObject points to. Does nothing if object is not found. </p>
</div>
<h3><a name="4240">end</a> <img src="images/inline.gif" alt="inline" title="inline" style="vertical-align:baseline;" border="0" /> </h3>
<p class="decl"><a href="Poco.ClassLoader.Iterator.html" title="class Poco::ClassLoader::Iterator">Iterator</a> end() const;</p>
<div class="description">
<p></p>
</div>
<h3><a name="4217">findClass</a> <img src="images/inline.gif" alt="inline" title="inline" style="vertical-align:baseline;" border="0" /> </h3>
<p class="decl">const <a href="Poco.ClassLoader.html#4178" title="Poco::ClassLoader::Meta">Meta</a> * findClass(<br /> const std::string & className<br />) const;</p>
<div class="description">
<p>Returns a pointer to the <a href="Poco.MetaObject.html" title="class Poco::MetaObject">MetaObject</a> for the given class, or a null pointer if the class is not known. </p>
</div>
<h3><a name="4233">findManifest</a> <img src="images/inline.gif" alt="inline" title="inline" style="vertical-align:baseline;" border="0" /> </h3>
<p class="decl">const <a href="Poco.ClassLoader.html#4179" title="Poco::ClassLoader::Manif">Manif</a> * findManifest(<br /> const std::string & path<br />) const;</p>
<div class="description">
<p>Returns a pointer to the <a href="Poco.Manifest.html" title="class Poco::Manifest">Manifest</a> for the given library, or a null pointer if the library has not been loaded. </p>
</div>
<h3><a name="4223">instance</a> <img src="images/inline.gif" alt="inline" title="inline" style="vertical-align:baseline;" border="0" /> </h3>
<p class="decl">Base & instance(<br /> const std::string & className<br />) const;</p>
<div class="description">
<p>Returns a reference to the sole instance of the given class. The class must be a singleton, otherwise an <a href="Poco.InvalidAccessException.html" title="class Poco::InvalidAccessException">InvalidAccessException</a> will be thrown. Throws a <a href="Poco.NotFoundException.html" title="class Poco::NotFoundException">NotFoundException</a> if the class is not known. </p>
</div>
<h3><a name="4230">isAutoDelete</a> <img src="images/inline.gif" alt="inline" title="inline" style="vertical-align:baseline;" border="0" /> </h3>
<p class="decl">bool isAutoDelete(<br /> const std::string & className,<br /> Base * pObject<br />) const;</p>
<div class="description">
<p>Returns true if the object is automatically deleted by its meta object. </p>
</div>
<h3><a name="4237">isLibraryLoaded</a> <img src="images/inline.gif" alt="inline" title="inline" style="vertical-align:baseline;" border="0" /> </h3>
<p class="decl">bool isLibraryLoaded(<br /> const std::string & path<br />) const;</p>
<div class="description">
<p>Returns true if the library with the given name has already been loaded. </p>
</div>
<h3><a name="4210">loadLibrary</a> <img src="images/inline.gif" alt="inline" title="inline" style="vertical-align:baseline;" border="0" /> </h3>
<p class="decl">void loadLibrary(<br /> const std::string & path,<br /> const std::string & manifest<br />);</p>
<div class="description">
<p>Loads a library from the given path, using the given manifest. Does nothing if the library is already loaded. Throws a <a href="Poco.LibraryLoadException.html" title="class Poco::LibraryLoadException">LibraryLoadException</a> if the library cannot be loaded or does not have a <a href="Poco.Manifest.html" title="class Poco::Manifest">Manifest</a>. If the library exports a function named "pocoInitializeLibrary", this function is executed. If called multiple times for the same library, the number of calls to <a href="Poco.ClassLoader.html#4215" title="Poco::ClassLoader::unloadLibrary()">unloadLibrary</a>() must be the same for the library to become unloaded. </p>
</div>
<h3><a name="4213">loadLibrary</a> <img src="images/inline.gif" alt="inline" title="inline" style="vertical-align:baseline;" border="0" /> </h3>
<p class="decl">void loadLibrary(<br /> const std::string & path<br />);</p>
<div class="description">
<p>Loads a library from the given path. Does nothing if the library is already loaded. Throws a <a href="Poco.LibraryLoadException.html" title="class Poco::LibraryLoadException">LibraryLoadException</a> if the library cannot be loaded or does not have a <a href="Poco.Manifest.html" title="class Poco::Manifest">Manifest</a>. If the library exports a function named "pocoInitializeLibrary", this function is executed. If called multiple times for the same library, the number of calls to <a href="Poco.ClassLoader.html#4215" title="Poco::ClassLoader::unloadLibrary()">unloadLibrary</a>() must be the same for the library to become unloaded. </p>
<p>Equivalent to <a href="Poco.ClassLoader.html#4210" title="Poco::ClassLoader::loadLibrary()">loadLibrary</a>(path, ""). </p>
</div>
<h3><a name="4235">manifestFor</a> <img src="images/inline.gif" alt="inline" title="inline" style="vertical-align:baseline;" border="0" /> </h3>
<p class="decl">const <a href="Poco.ClassLoader.html#4179" title="Poco::ClassLoader::Manif">Manif</a> & manifestFor(<br /> const std::string & path<br />) const;</p>
<div class="description">
<p>Returns a reference to the <a href="Poco.Manifest.html" title="class Poco::Manifest">Manifest</a> for the given library Throws a <a href="Poco.NotFoundException.html" title="class Poco::NotFoundException">NotFoundException</a> if the library has not been loaded. </p>
</div>
<h3><a name="4215">unloadLibrary</a> <img src="images/inline.gif" alt="inline" title="inline" style="vertical-align:baseline;" border="0" /> </h3>
<p class="decl">void unloadLibrary(<br /> const std::string & path<br />);</p>
<div class="description">
<p>Unloads the given library. Be extremely cautious when unloading shared libraries. If objects from the library are still referenced somewhere, a total crash is very likely. If the library exports a function named "pocoUninitializeLibrary", this function is executed before it is unloaded. If <a href="Poco.ClassLoader.html#4210" title="Poco::ClassLoader::loadLibrary()">loadLibrary</a>() has been called multiple times for the same library, the number of calls to <a href="Poco.ClassLoader.html#4215" title="Poco::ClassLoader::unloadLibrary()">unloadLibrary</a>() must be the same for the library to become unloaded. </p>
</div>
<p class="footer">POCO C++ Libraries 1.3.6-all<br />
Copyright © 2009, <a href="http://pocoproject.org/" target="_blank">Applied Informatics Software Engineering GmbH and Contributors</a></p>
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