~oif-team/ubuntu/natty/qt4-x11/xi2.1

<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="mainclasses.html"><font color="#004faf">Main Classes</font></a> · <a href="annotated.html"><font color="#004faf">Annotated</font></a> · <a href="groups.html"><font color="#004faf">Grouped Classes</font></a> · <a href="functions.html"><font color="#004faf">Functions</font></a></td>

<td align="right" valign="top" width="230"><img src="images/trolltech-logo.png" align="right" width="203" height="32" border="0" /></td></tr></table><h1 align="center">QWriteLocker Class Reference</h1>

<p>The QWriteLocker class is a convenience class that simplifies locking and unlocking read-write locks for write access. <a href="#details">More...</a></p>

<pre>#include <QWriteLocker></pre><p>Part of the <a href="qtcore.html">QtCore</a> module.</p>

<p><b>Note:</b> All the functions in this class are <a href="threads.html#thread-safe">thread-safe</a>.</p>

<ul>

<li><a href="qwritelocker-members.html">List of all members, including inherited members</a></li>

</ul>

<h3>Public Functions</h3>

<ul>

<li><div class="fn"/><b><a href="qwritelocker.html#QWriteLocker">QWriteLocker</a></b> ( QReadWriteLock * <i>lock</i> )</li>

<li><div class="fn"/><b><a href="qwritelocker.html#dtor.QWriteLocker">~QWriteLocker</a></b> ()</li>

<li><div class="fn"/>QReadWriteLock * <b><a href="qwritelocker.html#readWriteLock">readWriteLock</a></b> () const</li>

<li><div class="fn"/>void <b><a href="qwritelocker.html#relock">relock</a></b> ()</li>

<li><div class="fn"/>void <b><a href="qwritelocker.html#unlock">unlock</a></b> ()</li>

</ul>

<hr />

<h2>Detailed Description</h2>

<p>The QWriteLocker class is a convenience class that simplifies locking and unlocking read-write locks for write access.</p>

<p>The purpose of QWriteLocker (and <a href="qreadlocker.html">QReadLocker</a> is to simplify <a href="qreadwritelock.html">QReadWriteLock</a> locking and unlocking. Locking and unlocking statements or in exception handling code is error-prone and difficult to debug. QWriteLocker can be used in such situations to ensure that the state of the lock is always well-defined.</p>

<p>Here's an example that uses QWriteLocker to lock and unlock a read-write lock for writing:</p>

<pre>  QReadWriteLock lock;

void writeData(const QByteArray &data)

{

QWriteLocker locker(&lock);

...

}</pre>

<p>It is equivalent to the following code:</p>

<pre>  QReadWriteLock lock;

void writeData(const QByteArray &data)

{

locker.lockForWrite();

...

locker.unlock();

}</pre>

<p>The <a href="qmutexlocker.html">QMutexLocker</a> documentation shows examples where the use of a locker object greatly simplifies programming.</p>

<p>See also <a href="qreadlocker.html">QReadLocker</a> and <a href="qreadwritelock.html">QReadWriteLock</a>.</p>

<hr />

<h2>Member Function Documentation</h2>

<h3 class="fn"><a name="QWriteLocker"></a>QWriteLocker::QWriteLocker ( <a href="qreadwritelock.html">QReadWriteLock</a> * <i>lock</i> )</h3>

<p>Constructs a <a href="qwritelocker.html">QWriteLocker</a> and locks <i>lock</i> for writing. The lock will be unlocked when the <a href="qwritelocker.html">QWriteLocker</a> is destroyed. If <tt>lock</tt> is zero, <a href="qwritelocker.html">QWriteLocker</a> does nothing.</p>

<p>See also <a href="qreadwritelock.html#lockForWrite">QReadWriteLock::lockForWrite</a>().</p>

<h3 class="fn"><a name="dtor.QWriteLocker"></a>QWriteLocker::~QWriteLocker ()</h3>

<p>Destroys the <a href="qwritelocker.html">QWriteLocker</a> and unlocks the lock that was passed to the constructor.</p>

<p>See also <a href="qreadwritelock.html#unlock">QReadWriteLock::unlock</a>().</p>

<h3 class="fn"><a name="readWriteLock"></a><a href="qreadwritelock.html">QReadWriteLock</a> * QWriteLocker::readWriteLock () const</h3>

<p>Returns a pointer to the read-write lock that was passed to the constructor.</p>

<h3 class="fn"><a name="relock"></a>void QWriteLocker::relock ()</h3>

<p>Relocks an unlocked lock.</p>

<p>See also <a href="qwritelocker.html#unlock">unlock</a>().</p>

<h3 class="fn"><a name="unlock"></a>void QWriteLocker::unlock ()</h3>

<p>Unlocks the lock associated with this locker.</p>

<p>See also <a href="qreadwritelock.html#unlock">QReadWriteLock::unlock</a>().</p>

<td width="40%" align="center"><a href="trademarks.html">Trademarks</a></td>

</tr></table></div></address></body>

</html>

Older »