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<li class="level1"><a href="#static-public-members">Static Public Members</a></li>
<li class="level1"><a href="#related-non-members">Related Non-Members</a></li>
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<h1 class="title">QMetaType Class Reference</h1>
<!-- $$$QMetaType-brief -->
<p>The QMetaType class manages named types in the meta-object system. <a href="#details">More...</a></p>
<!-- @@@QMetaType -->
<pre class="cpp"> <span class="preprocessor">#include <QMetaType></span></pre><p><b>Note:</b> All functions in this class are <a href="threads-reentrancy.html#thread-safe">thread-safe</a>.</p>
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<li><a href="qmetatype-members.html">List of all members, including inherited members</a></li>
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<a name="public-types"></a>
<h2>Public Types</h2>
<table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> enum </td><td class="memItemRight bottomAlign"><b><a href="qmetatype.html#Type-enum">Type</a></b> { Void, Bool, Int, UInt, ..., User }</td></tr>
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<a name="static-public-members"></a>
<h2>Static Public Members</h2>
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<tr><td class="memItemLeft rightAlign topAlign"> void * </td><td class="memItemRight bottomAlign"><b><a href="qmetatype.html#construct">construct</a></b> ( int <i>type</i>, const void * <i>copy</i> = 0 )</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qmetatype.html#destroy">destroy</a></b> ( int <i>type</i>, void * <i>data</i> )</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> bool </td><td class="memItemRight bottomAlign"><b><a href="qmetatype.html#isRegistered">isRegistered</a></b> ( int <i>type</i> )</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> bool </td><td class="memItemRight bottomAlign"><b><a href="qmetatype.html#load">load</a></b> ( QDataStream & <i>stream</i>, int <i>type</i>, void * <i>data</i> )</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> bool </td><td class="memItemRight bottomAlign"><b><a href="qmetatype.html#save">save</a></b> ( QDataStream & <i>stream</i>, int <i>type</i>, const void * <i>data</i> )</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> int </td><td class="memItemRight bottomAlign"><b><a href="qmetatype.html#type">type</a></b> ( const char * <i>typeName</i> )</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> const char * </td><td class="memItemRight bottomAlign"><b><a href="qmetatype.html#typeName">typeName</a></b> ( int <i>type</i> )</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qmetatype.html#unregisterType">unregisterType</a></b> ( const char * <i>typeName</i> )</td></tr>
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<h2>Related Non-Members</h2>
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<tr><td class="memItemLeft rightAlign topAlign"> int </td><td class="memItemRight bottomAlign"><b><a href="qmetatype.html#qMetaTypeId">qMetaTypeId</a></b> ()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> int </td><td class="memItemRight bottomAlign"><b><a href="qmetatype.html#qRegisterMetaType">qRegisterMetaType</a></b> ( const char * <i>typeName</i> )</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> int </td><td class="memItemRight bottomAlign"><b><a href="qmetatype.html#qRegisterMetaType-2">qRegisterMetaType</a></b> ()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qmetatype.html#qRegisterMetaTypeStreamOperators">qRegisterMetaTypeStreamOperators</a></b> ( const char * <i>typeName</i> )</td></tr>
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<a name="macros"></a>
<h2>Macros</h2>
<table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qmetatype.html#Q_DECLARE_METATYPE">Q_DECLARE_METATYPE</a></b> ( <i>Type</i> )</td></tr>
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<a name="details"></a>
<!-- $$$QMetaType-description -->
<div class="descr">
<h2>Detailed Description</h2>
<p>The QMetaType class manages named types in the meta-object system.</p>
<p>The class is used as a helper to marshall types in <a href="qmetatype.html#Type-enum">QVariant</a> and in queued signals and slots connections. It associates a type name to a type so that it can be created and destructed dynamically at run-time. Declare new types with <a href="qmetatype.html#Q_DECLARE_METATYPE">Q_DECLARE_METATYPE</a>() to make them available to <a href="qmetatype.html#Type-enum">QVariant</a> and other template-based functions. Call <a href="qmetatype.html#qRegisterMetaType">qRegisterMetaType</a>() to make type available to non-template based functions, such as the queued signal and slot connections.</p>
<p>Any class or struct that has a public default constructor, a public copy constructor, and a public destructor can be registered.</p>
<p>The following code allocates and destructs an instance of <tt>MyClass</tt>:</p>
<pre class="cpp"> <span class="type">int</span> id <span class="operator">=</span> <span class="type">QMetaType</span><span class="operator">::</span><a href="qmetatype.html#type">type</a>(<span class="string">"MyClass"</span>);
<span class="keyword">if</span> (id <span class="operator">!</span><span class="operator">=</span> <span class="number">0</span>) {
<span class="type">void</span> <span class="operator">*</span>myClassPtr <span class="operator">=</span> <span class="type">QMetaType</span><span class="operator">::</span>construct(id);
<span class="operator">.</span><span class="operator">.</span><span class="operator">.</span>
<span class="type">QMetaType</span><span class="operator">::</span>destroy(id<span class="operator">,</span> myClassPtr);
myClassPtr <span class="operator">=</span> <span class="number">0</span>;
}</pre>
<p>If we want the stream operators <tt>operator<<()</tt> and <tt>operator>>()</tt> to work on <a href="qmetatype.html#Type-enum">QVariant</a> objects that store custom types, the custom type must provide <tt>operator<<()</tt> and <tt>operator>>()</tt> operators.</p>
</div>
<p><b>See also </b><a href="qmetatype.html#Q_DECLARE_METATYPE">Q_DECLARE_METATYPE</a>(), <a href="qvariant.html#setValue">QVariant::setValue</a>(), <a href="qvariant.html#value">QVariant::value</a>(), and <a href="qvariant.html#fromValue">QVariant::fromValue</a>().</p>
<!-- @@@QMetaType -->
<div class="types">
<h2>Member Type Documentation</h2>
<!-- $$$Type$$$Void$$$Bool$$$Int$$$UInt$$$LongLong$$$ULongLong$$$Double$$$QChar$$$QVariantMap$$$QVariantList$$$QString$$$QStringList$$$QByteArray$$$QBitArray$$$QDate$$$QTime$$$QDateTime$$$QUrl$$$QLocale$$$QRect$$$QRectF$$$QSize$$$QSizeF$$$QLine$$$QLineF$$$QPoint$$$QPointF$$$QRegExp$$$QVariantHash$$$QEasingCurve$$$LastCoreType$$$FirstGuiType$$$QColorGroup$$$QFont$$$QPixmap$$$QBrush$$$QColor$$$QPalette$$$QIcon$$$QImage$$$QPolygon$$$QRegion$$$QBitmap$$$QCursor$$$QSizePolicy$$$QKeySequence$$$QPen$$$QTextLength$$$QTextFormat$$$QMatrix$$$QTransform$$$QMatrix4x4$$$QVector2D$$$QVector3D$$$QVector4D$$$QQuaternion$$$LastGuiType$$$FirstCoreExtType$$$VoidStar$$$Long$$$Short$$$Char$$$ULong$$$UShort$$$UChar$$$Float$$$QObjectStar$$$QWidgetStar$$$QVariant$$$LastCoreExtType$$$QReal$$$User -->
<h3 class="fn"><a name="Type-enum"></a>enum QMetaType::<span class="name">Type</span></h3>
<p>These are the built-in types supported by <a href="qmetatype.html">QMetaType</a>:</p>
<table class="valuelist"><tr valign="top" class="odd"><th class="tblConst">Constant</th><th class="tblval">Value</th><th class="tbldscr">Description</th></tr>
<tr><td class="topAlign"><tt>QMetaType::Void</tt></td><td class="topAlign"><tt>0</tt></td><td class="topAlign"><tt>void</tt></td></tr>
<tr><td class="topAlign"><tt>QMetaType::Bool</tt></td><td class="topAlign"><tt>1</tt></td><td class="topAlign"><tt>bool</tt></td></tr>
<tr><td class="topAlign"><tt>QMetaType::Int</tt></td><td class="topAlign"><tt>2</tt></td><td class="topAlign"><tt>int</tt></td></tr>
<tr><td class="topAlign"><tt>QMetaType::UInt</tt></td><td class="topAlign"><tt>3</tt></td><td class="topAlign"><tt>unsigned int</tt></td></tr>
<tr><td class="topAlign"><tt>QMetaType::Double</tt></td><td class="topAlign"><tt>6</tt></td><td class="topAlign"><tt>double</tt></td></tr>
<tr><td class="topAlign"><tt>QMetaType::QChar</tt></td><td class="topAlign"><tt>7</tt></td><td class="topAlign">QChar</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QString</tt></td><td class="topAlign"><tt>10</tt></td><td class="topAlign">QString</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QByteArray</tt></td><td class="topAlign"><tt>12</tt></td><td class="topAlign">QByteArray</td></tr>
<tr><td class="topAlign"><tt>QMetaType::VoidStar</tt></td><td class="topAlign"><tt>128</tt></td><td class="topAlign"><tt>void *</tt></td></tr>
<tr><td class="topAlign"><tt>QMetaType::Long</tt></td><td class="topAlign"><tt>129</tt></td><td class="topAlign"><tt>long</tt></td></tr>
<tr><td class="topAlign"><tt>QMetaType::LongLong</tt></td><td class="topAlign"><tt>4</tt></td><td class="topAlign">LongLong</td></tr>
<tr><td class="topAlign"><tt>QMetaType::Short</tt></td><td class="topAlign"><tt>130</tt></td><td class="topAlign"><tt>short</tt></td></tr>
<tr><td class="topAlign"><tt>QMetaType::Char</tt></td><td class="topAlign"><tt>131</tt></td><td class="topAlign"><tt>char</tt></td></tr>
<tr><td class="topAlign"><tt>QMetaType::ULong</tt></td><td class="topAlign"><tt>132</tt></td><td class="topAlign"><tt>unsigned long</tt></td></tr>
<tr><td class="topAlign"><tt>QMetaType::ULongLong</tt></td><td class="topAlign"><tt>5</tt></td><td class="topAlign">ULongLong</td></tr>
<tr><td class="topAlign"><tt>QMetaType::UShort</tt></td><td class="topAlign"><tt>133</tt></td><td class="topAlign"><tt>unsigned short</tt></td></tr>
<tr><td class="topAlign"><tt>QMetaType::UChar</tt></td><td class="topAlign"><tt>134</tt></td><td class="topAlign"><tt>unsigned char</tt></td></tr>
<tr><td class="topAlign"><tt>QMetaType::Float</tt></td><td class="topAlign"><tt>135</tt></td><td class="topAlign"><tt>float</tt></td></tr>
<tr><td class="topAlign"><tt>QMetaType::QObjectStar</tt></td><td class="topAlign"><tt>136</tt></td><td class="topAlign"><a href="qobject.html">QObject</a> *</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QWidgetStar</tt></td><td class="topAlign"><tt>137</tt></td><td class="topAlign"><a href="qwidget.html">QWidget</a> *</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QVariant</tt></td><td class="topAlign"><tt>138</tt></td><td class="topAlign">QVariant</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QColorGroup</tt></td><td class="topAlign"><tt>63</tt></td><td class="topAlign">QColorGroup</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QCursor</tt></td><td class="topAlign"><tt>74</tt></td><td class="topAlign">QCursor</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QDate</tt></td><td class="topAlign"><tt>14</tt></td><td class="topAlign">QDate</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QSize</tt></td><td class="topAlign"><tt>21</tt></td><td class="topAlign">QSize</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QTime</tt></td><td class="topAlign"><tt>15</tt></td><td class="topAlign">QTime</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QVariantList</tt></td><td class="topAlign"><tt>9</tt></td><td class="topAlign">QVariantList</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QPolygon</tt></td><td class="topAlign"><tt>71</tt></td><td class="topAlign">QPolygon</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QColor</tt></td><td class="topAlign"><tt>67</tt></td><td class="topAlign">QColor</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QSizeF</tt></td><td class="topAlign"><tt>22</tt></td><td class="topAlign">QSizeF</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QRectF</tt></td><td class="topAlign"><tt>20</tt></td><td class="topAlign">QRectF</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QLine</tt></td><td class="topAlign"><tt>23</tt></td><td class="topAlign">QLine</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QTextLength</tt></td><td class="topAlign"><tt>78</tt></td><td class="topAlign">QTextLength</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QStringList</tt></td><td class="topAlign"><tt>11</tt></td><td class="topAlign">QStringList</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QVariantMap</tt></td><td class="topAlign"><tt>8</tt></td><td class="topAlign">QVariantMap</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QVariantHash</tt></td><td class="topAlign"><tt>28</tt></td><td class="topAlign">QVariantHash</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QIcon</tt></td><td class="topAlign"><tt>69</tt></td><td class="topAlign">QIcon</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QPen</tt></td><td class="topAlign"><tt>77</tt></td><td class="topAlign">QPen</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QLineF</tt></td><td class="topAlign"><tt>24</tt></td><td class="topAlign">QLineF</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QTextFormat</tt></td><td class="topAlign"><tt>79</tt></td><td class="topAlign">QTextFormat</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QRect</tt></td><td class="topAlign"><tt>19</tt></td><td class="topAlign">QRect</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QPoint</tt></td><td class="topAlign"><tt>25</tt></td><td class="topAlign">QPoint</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QUrl</tt></td><td class="topAlign"><tt>17</tt></td><td class="topAlign">QUrl</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QRegExp</tt></td><td class="topAlign"><tt>27</tt></td><td class="topAlign">QRegExp</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QDateTime</tt></td><td class="topAlign"><tt>16</tt></td><td class="topAlign">QDateTime</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QPointF</tt></td><td class="topAlign"><tt>26</tt></td><td class="topAlign">QPointF</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QPalette</tt></td><td class="topAlign"><tt>68</tt></td><td class="topAlign">QPalette</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QFont</tt></td><td class="topAlign"><tt>64</tt></td><td class="topAlign">QFont</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QBrush</tt></td><td class="topAlign"><tt>66</tt></td><td class="topAlign">QBrush</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QRegion</tt></td><td class="topAlign"><tt>72</tt></td><td class="topAlign">QRegion</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QBitArray</tt></td><td class="topAlign"><tt>13</tt></td><td class="topAlign">QBitArray</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QImage</tt></td><td class="topAlign"><tt>70</tt></td><td class="topAlign">QImage</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QKeySequence</tt></td><td class="topAlign"><tt>76</tt></td><td class="topAlign">QKeySequence</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QSizePolicy</tt></td><td class="topAlign"><tt>75</tt></td><td class="topAlign">QSizePolicy</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QPixmap</tt></td><td class="topAlign"><tt>65</tt></td><td class="topAlign">QPixmap</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QLocale</tt></td><td class="topAlign"><tt>18</tt></td><td class="topAlign">QLocale</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QBitmap</tt></td><td class="topAlign"><tt>73</tt></td><td class="topAlign">QBitmap</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QMatrix</tt></td><td class="topAlign"><tt>80</tt></td><td class="topAlign">QMatrix</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QTransform</tt></td><td class="topAlign"><tt>81</tt></td><td class="topAlign">QTransform</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QMatrix4x4</tt></td><td class="topAlign"><tt>82</tt></td><td class="topAlign">QMatrix4x4</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QVector2D</tt></td><td class="topAlign"><tt>83</tt></td><td class="topAlign">QVector2D</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QVector3D</tt></td><td class="topAlign"><tt>84</tt></td><td class="topAlign">QVector3D</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QVector4D</tt></td><td class="topAlign"><tt>85</tt></td><td class="topAlign">QVector4D</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QQuaternion</tt></td><td class="topAlign"><tt>86</tt></td><td class="topAlign">QQuaternion</td></tr>
<tr><td class="topAlign"><tt>QMetaType::QEasingCurve</tt></td><td class="topAlign"><tt>29</tt></td><td class="topAlign">QEasingCurve</td></tr>
<tr><td class="topAlign"><tt>QMetaType::User</tt></td><td class="topAlign"><tt>256</tt></td><td class="topAlign">Base value for user types</td></tr>
</table>
<p>Additional types can be registered using <a href="qmetatype.html#Q_DECLARE_METATYPE">Q_DECLARE_METATYPE</a>().</p>
<p><b>See also </b><a href="qmetatype.html#type">type</a>() and <a href="qmetatype.html#typeName">typeName</a>().</p>
<!-- @@@Type -->
</div>
<div class="func">
<h2>Member Function Documentation</h2>
<!-- $$$construct[overload1]$$$constructintconstvoid* -->
<h3 class="fn"><a name="construct"></a><span class="type">void</span> * QMetaType::<span class="name">construct</span> ( <span class="type">int</span> <i>type</i>, const <span class="type">void</span> * <i>copy</i> = 0 )<tt> [static]</tt></h3>
<p>Returns a copy of <i>copy</i>, assuming it is of type <i>type</i>. If <i>copy</i> is zero, creates a default type.</p>
<p><b>See also </b><a href="qmetatype.html#destroy">destroy</a>(), <a href="qmetatype.html#isRegistered">isRegistered</a>(), and <a href="qmetatype.html#Type-enum">Type</a>.</p>
<!-- @@@construct -->
<!-- $$$destroy[overload1]$$$destroyintvoid* -->
<h3 class="fn"><a name="destroy"></a><span class="type">void</span> QMetaType::<span class="name">destroy</span> ( <span class="type">int</span> <i>type</i>, <span class="type">void</span> * <i>data</i> )<tt> [static]</tt></h3>
<p>Destroys the <i>data</i>, assuming it is of the <i>type</i> given.</p>
<p><b>See also </b><a href="qmetatype.html#construct">construct</a>(), <a href="qmetatype.html#isRegistered">isRegistered</a>(), and <a href="qmetatype.html#Type-enum">Type</a>.</p>
<!-- @@@destroy -->
<!-- $$$isRegistered[overload1]$$$isRegisteredint -->
<h3 class="fn"><a name="isRegistered"></a><span class="type">bool</span> QMetaType::<span class="name">isRegistered</span> ( <span class="type">int</span> <i>type</i> )<tt> [static]</tt></h3>
<p>Returns true if the datatype with ID <i>type</i> is registered; otherwise returns false.</p>
<p><b>See also </b><a href="qmetatype.html#type">type</a>(), <a href="qmetatype.html#typeName">typeName</a>(), and <a href="qmetatype.html#Type-enum">Type</a>.</p>
<!-- @@@isRegistered -->
<!-- $$$load[overload1]$$$loadQDataStream&intvoid* -->
<h3 class="fn"><a name="load"></a><span class="type">bool</span> QMetaType::<span class="name">load</span> ( <span class="type"><a href="qdatastream.html">QDataStream</a></span> & <i>stream</i>, <span class="type">int</span> <i>type</i>, <span class="type">void</span> * <i>data</i> )<tt> [static]</tt></h3>
<p>Reads the object of the specified <i>type</i> from the given <i>stream</i> into <i>data</i>. Returns true if the object is loaded successfully; otherwise returns false.</p>
<p>The type must have been registered with <a href="qmetatype.html#qRegisterMetaType">qRegisterMetaType</a>() and <a href="qmetatype.html#qRegisterMetaTypeStreamOperators">qRegisterMetaTypeStreamOperators</a>() beforehand.</p>
<p>Normally, you should not need to call this function directly. Instead, use <a href="qmetatype.html#Type-enum">QVariant</a>'s <tt>operator>>()</tt>, which relies on load() to stream custom types.</p>
<p><b>See also </b><a href="qmetatype.html#save">save</a>() and <a href="qmetatype.html#qRegisterMetaTypeStreamOperators">qRegisterMetaTypeStreamOperators</a>().</p>
<!-- @@@load -->
<!-- $$$save[overload1]$$$saveQDataStream&intconstvoid* -->
<h3 class="fn"><a name="save"></a><span class="type">bool</span> QMetaType::<span class="name">save</span> ( <span class="type"><a href="qdatastream.html">QDataStream</a></span> & <i>stream</i>, <span class="type">int</span> <i>type</i>, const <span class="type">void</span> * <i>data</i> )<tt> [static]</tt></h3>
<p>Writes the object pointed to by <i>data</i> with the ID <i>type</i> to the given <i>stream</i>. Returns true if the object is saved successfully; otherwise returns false.</p>
<p>The type must have been registered with <a href="qmetatype.html#qRegisterMetaType">qRegisterMetaType</a>() and <a href="qmetatype.html#qRegisterMetaTypeStreamOperators">qRegisterMetaTypeStreamOperators</a>() beforehand.</p>
<p>Normally, you should not need to call this function directly. Instead, use <a href="qmetatype.html#Type-enum">QVariant</a>'s <tt>operator<<()</tt>, which relies on save() to stream custom types.</p>
<p><b>See also </b><a href="qmetatype.html#load">load</a>() and <a href="qmetatype.html#qRegisterMetaTypeStreamOperators">qRegisterMetaTypeStreamOperators</a>().</p>
<!-- @@@save -->
<!-- $$$type[overload1]$$$typeconstchar* -->
<h3 class="fn"><a name="type"></a><span class="type">int</span> QMetaType::<span class="name">type</span> ( const <span class="type">char</span> * <i>typeName</i> )<tt> [static]</tt></h3>
<p>Returns a handle to the type called <i>typeName</i>, or 0 if there is no such type.</p>
<p><b>See also </b><a href="qmetatype.html#isRegistered">isRegistered</a>(), <a href="qmetatype.html#typeName">typeName</a>(), and <a href="qmetatype.html#Type-enum">Type</a>.</p>
<!-- @@@type -->
<!-- $$$typeName[overload1]$$$typeNameint -->
<h3 class="fn"><a name="typeName"></a>const <span class="type">char</span> * QMetaType::<span class="name">typeName</span> ( <span class="type">int</span> <i>type</i> )<tt> [static]</tt></h3>
<p>Returns the type name associated with the given <i>type</i>, or 0 if no matching type was found. The returned pointer must not be deleted.</p>
<p><b>See also </b><a href="qmetatype.html#type">type</a>(), <a href="qmetatype.html#isRegistered">isRegistered</a>(), and <a href="qmetatype.html#Type-enum">Type</a>.</p>
<!-- @@@typeName -->
<!-- $$$unregisterType[overload1]$$$unregisterTypeconstchar* -->
<h3 class="fn"><a name="unregisterType"></a><span class="type">void</span> QMetaType::<span class="name">unregisterType</span> ( const <span class="type">char</span> * <i>typeName</i> )<tt> [static]</tt></h3>
<p>Unregisters a user type, with <i>typeName</i>.</p>
<p>This function was introduced in Qt 4.4.</p>
<p><b>See also </b><a href="qmetatype.html#type">type</a>() and <a href="qmetatype.html#typeName">typeName</a>().</p>
<!-- @@@unregisterType -->
</div>
<div class="relnonmem">
<h2>Related Non-Members</h2>
<!-- $$$qMetaTypeId[overload1]$$$qMetaTypeId -->
<h3 class="fn"><a name="qMetaTypeId"></a><span class="type">int</span> <span class="name">qMetaTypeId</span> ()</h3>
<p>Returns the meta type id of type <tt>T</tt> at compile time. If the type was not declared with <a href="qmetatype.html#Q_DECLARE_METATYPE">Q_DECLARE_METATYPE</a>(), compilation will fail.</p>
<p>Typical usage:</p>
<pre class="cpp"> <span class="type">int</span> id <span class="operator">=</span> qMetaTypeId<span class="operator"><</span><span class="type"><a href="qstring.html">QString</a></span><span class="operator">></span>(); <span class="comment">// id is now QMetaType::QString</span>
id <span class="operator">=</span> qMetaTypeId<span class="operator"><</span>MyStruct<span class="operator">></span>(); <span class="comment">// compile error if MyStruct not declared</span></pre>
<p><a href="qmetatype.html#type">QMetaType::type</a>() returns the same ID as qMetaTypeId(), but does a lookup at runtime based on the name of the type. <a href="qmetatype.html#type">QMetaType::type</a>() is a bit slower, but compilation succeeds if a type is not registered.</p>
<p><b>Note:</b> This function is <a href="threads-reentrancy.html#thread-safe">thread-safe</a>.</p>
<p>This function was introduced in Qt 4.1.</p>
<p><b>See also </b><a href="qmetatype.html#Q_DECLARE_METATYPE">Q_DECLARE_METATYPE</a>() and <a href="qmetatype.html#type">QMetaType::type</a>().</p>
<!-- @@@qMetaTypeId -->
<!-- $$$qRegisterMetaType[overload1]$$$qRegisterMetaTypeconstchar* -->
<h3 class="fn"><a name="qRegisterMetaType"></a><span class="type">int</span> <span class="name">qRegisterMetaType</span> ( const <span class="type">char</span> * <i>typeName</i> )</h3>
<p>Registers the type name <i>typeName</i> for the type <tt>T</tt>. Returns the internal ID used by <a href="qmetatype.html">QMetaType</a>. Any class or struct that has a public default constructor, a public copy constructor and a public destructor can be registered.</p>
<p>After a type has been registered, you can create and destroy objects of that type dynamically at run-time.</p>
<p>This example registers the class <tt>MyClass</tt>:</p>
<pre class="cpp"> qRegisterMetaType<span class="operator"><</span>MyClass<span class="operator">></span>(<span class="string">"MyClass"</span>);</pre>
<p>This function is useful to register typedefs so they can be used by <a href="qmetaproperty.html">QMetaProperty</a>, or in QueuedConnections</p>
<pre class="cpp"> <span class="keyword">typedef</span> <span class="type"><a href="qstring.html">QString</a></span> CustomString;
qRegisterMetaType<span class="operator"><</span>CustomString<span class="operator">></span>(<span class="string">"CustomString"</span>);</pre>
<p><b>Note:</b> This function is <a href="threads-reentrancy.html#thread-safe">thread-safe</a>.</p>
<p><b>See also </b><a href="qmetatype.html#qRegisterMetaTypeStreamOperators">qRegisterMetaTypeStreamOperators</a>(), <a href="qmetatype.html#isRegistered">QMetaType::isRegistered</a>(), and <a href="qmetatype.html#Q_DECLARE_METATYPE">Q_DECLARE_METATYPE</a>().</p>
<!-- @@@qRegisterMetaType -->
<!-- $$$qRegisterMetaType$$$qRegisterMetaType -->
<h3 class="fn"><a name="qRegisterMetaType-2"></a><span class="type">int</span> <span class="name">qRegisterMetaType</span> ()</h3>
<p>Call this function to register the type <tt>T</tt>. <tt>T</tt> must be declared with <a href="qmetatype.html#Q_DECLARE_METATYPE">Q_DECLARE_METATYPE</a>(). Returns the meta type Id.</p>
<p>Example:</p>
<pre class="cpp"> <span class="type">int</span> id <span class="operator">=</span> <a href="qmetatype.html#qRegisterMetaType">qRegisterMetaType</a><span class="operator"><</span>MyStruct<span class="operator">></span>();</pre>
<p>To use the type <tt>T</tt> in <a href="qvariant.html">QVariant</a>, using <a href="qmetatype.html#Q_DECLARE_METATYPE">Q_DECLARE_METATYPE</a>() is sufficient. To use the type <tt>T</tt> in queued signal and slot connections, <tt>qRegisterMetaType<T>()</tt> must be called before the first connection is established.</p>
<p>Also, to use type <tt>T</tt> with the <a href="qobject.html#property">QObject::property</a>() API, <tt>qRegisterMetaType<T>()</tt> must be called before it is used, typically in the constructor of the class that uses <tt>T</tt>, or in the <tt>main()</tt> function.</p>
<p><b>Note:</b> This function is <a href="threads-reentrancy.html#thread-safe">thread-safe</a>.</p>
<p>This function was introduced in Qt 4.2.</p>
<p><b>See also </b><a href="qmetatype.html#Q_DECLARE_METATYPE">Q_DECLARE_METATYPE</a>().</p>
<!-- @@@qRegisterMetaType -->
<!-- $$$qRegisterMetaTypeStreamOperators[overload1]$$$qRegisterMetaTypeStreamOperatorsconstchar* -->
<h3 class="fn"><a name="qRegisterMetaTypeStreamOperators"></a><span class="type">void</span> <span class="name">qRegisterMetaTypeStreamOperators</span> ( const <span class="type">char</span> * <i>typeName</i> )</h3>
<p>Registers the stream operators for the type <tt>T</tt> called <i>typeName</i>.</p>
<p>Afterward, the type can be streamed using <a href="qmetatype.html#load">QMetaType::load</a>() and <a href="qmetatype.html#save">QMetaType::save</a>(). These functions are used when streaming a <a href="qvariant.html">QVariant</a>.</p>
<pre class="cpp"> qRegisterMetaTypeStreamOperators<span class="operator"><</span>MyClass<span class="operator">></span>(<span class="string">"MyClass"</span>);</pre>
<p>The stream operators should have the following signatures:</p>
<pre class="cpp"> <span class="type"><a href="qdatastream.html">QDataStream</a></span> <span class="operator">&</span><span class="keyword">operator</span><span class="operator"><</span><span class="operator"><</span>(<span class="type"><a href="qdatastream.html">QDataStream</a></span> <span class="operator">&</span>out<span class="operator">,</span> <span class="keyword">const</span> MyClass <span class="operator">&</span>myObj);
<span class="type"><a href="qdatastream.html">QDataStream</a></span> <span class="operator">&</span><span class="keyword">operator</span><span class="operator">></span><span class="operator">></span>(<span class="type"><a href="qdatastream.html">QDataStream</a></span> <span class="operator">&</span>in<span class="operator">,</span> MyClass <span class="operator">&</span>myObj);</pre>
<p><b>Note:</b> This function is <a href="threads-reentrancy.html#thread-safe">thread-safe</a>.</p>
<p><b>See also </b><a href="qmetatype.html#qRegisterMetaType">qRegisterMetaType</a>(), <a href="qmetatype.html#isRegistered">QMetaType::isRegistered</a>(), and <a href="qmetatype.html#Q_DECLARE_METATYPE">Q_DECLARE_METATYPE</a>().</p>
<!-- @@@qRegisterMetaTypeStreamOperators -->
</div>
<div class="macros">
<h2>Macro Documentation</h2>
<!-- $$$Q_DECLARE_METATYPE[overload1]$$$Q_DECLARE_METATYPE -->
<h3 class="fn"><a name="Q_DECLARE_METATYPE"></a><span class="name">Q_DECLARE_METATYPE</span> ( <i>Type</i> )</h3>
<p>This macro makes the type <i>Type</i> known to <a href="qmetatype.html">QMetaType</a> as long as it provides a public default constructor, a public copy constructor and a public destructor. It is needed to use the type <i>Type</i> as a custom type in <a href="qvariant.html">QVariant</a>.</p>
<p>Ideally, this macro should be placed below the declaration of the class or struct. If that is not possible, it can be put in a private header file which has to be included every time that type is used in a <a href="qvariant.html">QVariant</a>.</p>
<p>Adding a Q_DECLARE_METATYPE() makes the type known to all template based functions, including <a href="qvariant.html">QVariant</a>. Note that if you intend to use the type in <i>queued</i> signal and slot connections or in <a href="qobject.html">QObject</a>'s property system, you also have to call <a href="qmetatype.html#qRegisterMetaType">qRegisterMetaType</a>() since the names are resolved at runtime.</p>
<p>This example shows a typical use case of Q_DECLARE_METATYPE():</p>
<pre class="cpp"> <span class="keyword">struct</span> MyStruct
{
<span class="type">int</span> i;
<span class="operator">.</span><span class="operator">.</span><span class="operator">.</span>
};
Q_DECLARE_METATYPE(MyStruct)</pre>
<p>If <tt>MyStruct</tt> is in a namespace, the Q_DECLARE_METATYPE() macro has to be outside the namespace:</p>
<pre class="cpp"> <span class="keyword">namespace</span> MyNamespace
{
<span class="operator">.</span><span class="operator">.</span><span class="operator">.</span>
}
Q_DECLARE_METATYPE(MyNamespace<span class="operator">::</span>MyStruct)</pre>
<p>Since <tt>MyStruct</tt> is now known to <a href="qmetatype.html">QMetaType</a>, it can be used in <a href="qvariant.html">QVariant</a>:</p>
<pre class="cpp"> MyStruct s;
<span class="type"><a href="qvariant.html">QVariant</a></span> var;
var<span class="operator">.</span>setValue(s); <span class="comment">// copy s into the variant</span>
<span class="operator">.</span><span class="operator">.</span><span class="operator">.</span>
<span class="comment">// retrieve the value</span>
MyStruct s2 <span class="operator">=</span> var<span class="operator">.</span>value<span class="operator"><</span>MyStruct<span class="operator">></span>();</pre>
<p><b>See also </b><a href="qmetatype.html#qRegisterMetaType">qRegisterMetaType</a>().</p>
<!-- @@@Q_DECLARE_METATYPE -->
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