<?xml version="1.0" encoding="iso-8859-1"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <!-- qmutex.cpp --> <head> <title>Qt 4.6: Qt 3 Support Members for QMutex</title> <link href="classic.css" rel="stylesheet" type="text/css" /> </head> <body> <table border="0" cellpadding="0" cellspacing="0" width="100%"> <tr> <td align="left" valign="top" width="32"><a href="http://qt.nokia.com/"><img src="images/qt-logo.png" align="left" border="0" /></a></td> <td width="1"> </td><td class="postheader" valign="center"><a href="index.html"><font color="#004faf">Home</font></a> · <a href="classes.html"><font color="#004faf">All Classes</font></a> · <a href="functions.html"><font color="#004faf">All Functions</font></a> · <a href="overviews.html"><font color="#004faf">Overviews</font></a></td></tr></table><h1 class="title">Qt 3 Support Members for QMutex</h1> <p><b>The following class members are part of the <a href="qt3support.html">Qt 3 support layer</a>.</b> They are provided to help you port old code to Qt 4. We advise against using them in new code.</p> <p><ul><li><a href="qmutex.html">QMutex class reference</a></li></ul></p> <h2>Public Functions</h2> <table class="alignedsummary" border="0" cellpadding="0" cellspacing="0" width="100%"> <tr><td class="memItemLeft" align="right" valign="top"></td><td class="memItemRight" valign="bottom"><b><a href="qmutex-qt3.html#QMutex-2">QMutex</a></b> ( bool <i>recursive</i> )</td></tr> <tr><td class="memItemLeft" align="right" valign="top">bool </td><td class="memItemRight" valign="bottom"><b><a href="qmutex-qt3.html#locked">locked</a></b> ()</td></tr> </table> <hr /> <h2>Member Function Documentation</h2> <h3 class="fn"><a name="QMutex-2"></a>QMutex::QMutex ( bool <i>recursive</i> )</h3> <p>Use the constructor that takes a <a href="qmutex.html#RecursionMode-enum">RecursionMode</a> parameter instead.</p> <a name="//apple_ref/cpp/instm/QMutex/locked"></a> <h3 class="fn"><a name="locked"></a>bool QMutex::locked ()</h3> <p>Returns true if the mutex is locked by another thread; otherwise returns false.</p> <p>It is generally a bad idea to use this function, because code that uses it has a race condition. Use <a href="qmutex.html#tryLock">tryLock</a>() and <a href="qmutex.html#unlock">unlock</a>() instead.</p> <p>For example, if you have code like</p> <pre><font color="#404040"> bool isLocked = mutex.locked();</font></pre> <p>you can rewrite it as</p> <pre> bool isLocked = true; if (mutex.tryLock()) { mutex.unlock(); isLocked = false; }</pre> <p /><address><hr /><div align="center"> <table width="100%" cellspacing="0" border="0"><tr class="address"> <td width="40%" align="left">Copyright © 2010 Nokia Corporation and/or its subsidiary(-ies)</td> <td width="20%" align="center"><a href="trademarks.html">Trademarks</a></td> <td width="40%" align="right"><div align="right">Qt 4.6.3</div></td> </tr></table></div></address></body> </html>