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Copyright Frank Mori Hess 2007-2009

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<section last-revision="$Date: 2007-06-12 14:01:23 -0400 (Tue, 12 Jun 2007) $" id="signals2.faq">
  <title>Frequently Asked Questions</title>

  <using-namespace name="boost"/>
  <using-namespace name="boost::signals2"/>

  <qandaset>
    <qandaentry>
      <question>
        <para>Don't noncopyable signal semantics mean that a class
        with a signal member will be noncopyable as well?</para>
      </question>
      <answer>
        <para>No. The compiler will not be able to generate a copy
        constructor or copy assignment operator for your class if it
        has a signal as a member, but you are free to write your own
        copy constructor and/or copy assignment operator. Just don't
        try to copy the signal.</para>
      </answer>
    </qandaentry>
    <qandaentry>
      <question>
        <para>Is Boost.Signals2 thread-safe?</para>
      </question>
      <answer>
        <para>
          Yes, as long as the Mutex template parameter is not set to
          a fake mutex type like <classname>boost::signals2::dummy_mutex</classname>.
          Also, if your slots depend on objects which may be destroyed concurrently
          with signal invocation, you will need to use automatic connection management.
          That is, the objects will need to be owned by
          <classname>shared_ptr</classname> and passed to the slot's
          <methodname alt="slotN::track">track</methodname>() method before the slot is connected.
          The <classname>trackable</classname> scheme of automatic connection management
          is NOT thread-safe, and is only provided to ease porting of single-threaded
          code from Boost.Signals to Boost.Signals2.
        </para>
        <para>See the documentation section on <link linkend="signals2.thread-safety">thread-safety</link>
          for more information.
        </para>
      </answer>
    </qandaentry>
  </qandaset>
</section>
