 replace( size_type idx, <a class="reference external" href="compatible_smart_ptr.html"><em>compatible-smart-ptr</em></a>&lt;U&gt; x );
       bool      is_null( size_type idx ) const;

    };

} // namespace 'boost'
</pre>
</div>
<div class="section" id="semantics">
<h1>Semantics</h1>
<div class="section" id="semantics-modifiers">
<span id="modifiers"></span><h2>Semantics: modifiers</h2>
<ul>
<li><p class="first"><tt class="docutils literal">void push_front( T* x );</tt></p>
<blockquote>
<ul class="simple"