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    <p>One solution that springs to mind is partially specialized templates, which is what Martin York posted, but with a twist.</p> <p>I would recommend a special content_type-struct to supply the layout type, like so:</p> <pre><code>// content for non float types template&lt;typename T&gt; struct content_type { typedef typename T member_type; member_type x,y,z; member_type&amp; X { return x; } // ... // if access to optional members is needed, better use CT_ASSERT or similar member_type&amp; Pad { char assert_error_no_pad_here[0]; } }; // content for float types struct content_type&lt;float&gt; { typedef typename float member_type; member_type x, y, z, pad; member_type&amp; X { return x; } // ... member_type&amp; Pad { return pad; } }; template&lt;typename T&gt; class Vector3 { typedef typename content_type&lt;T&gt; layout_type; typedef typename content_type&lt;T&gt;::member_type member_type; layout_type _content; public: member_type&amp; X { return _content.X(); } memmber_type&amp; Pad { return _content.Pad(); } }; // or maybe, if memory layout is not important, just inherit (watch for virtual members) template&lt;typename T&gt; class Vector3 : public content_type&lt;T&gt; { typedef typename content_type&lt;T&gt; layout_type; typedef typename content_type&lt;T&gt;::member_type member_type; }; </code></pre> <p>The advantage is you only have to write Vector3 with all of its logic once.</p> <p>You need a moderately recent compiler to do that correctly, though (MSVC>7, gcc>3)</p>
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    1. COExcellent. Any idea how I should access those data members that are not part of the common denominator (e.g. "pad"). One approach is to disable their corresponding accessor member functions via Boost.enable_if in case those data members are not present. Thanks tabdamage.
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    2. COi added a solution for that, but maybe boost::enable_if is a bit cleaner. The best solution depends on your actual use, to get the runtime logic as clean as possible, the type definitions need to be a little more complicated.
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