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<title>The magic functions __sleep and __wakeup</title>
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<h2 class="title">The magic functions <em>__sleep</em> and <em>__wakeup</em></h2>
<p class="para">
<span class="function"><a href="function.serialize.html" class="function">serialize()</a></span> checks if your class has a function with
the magic name <em>__sleep</em>. If so, that function is
being run prior to any serialization. It can clean up the object
and is supposed to return an array with the names of all variables
of that object that should be serialized.
If the method doesn't return anything then <strong><code>NULL</code></strong> is serialized and
<strong><code>E_NOTICE</code></strong> is issued.
</p>
<p class="para">
The intended use of <em>__sleep</em> is to commit pending
data or perform similar cleanup tasks. Also, the function is
useful if you have very large objects which need not be
saved completely.
</p>
<p class="para">
Conversely, <span class="function"><a href="function.unserialize.html" class="function">unserialize()</a></span> checks for the
presence of a function with the magic name
<em>__wakeup</em>. If present, this function can
reconstruct any resources that object may have.
</p>
<p class="para">
The intended use of <em>__wakeup</em> is to
reestablish any database connections that may have been lost
during serialization and perform other reinitialization
tasks.
</p>
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