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    <p>It seems that in your particular example nothing in <code>fcn</code> function actually depends on class <code>A</code>. It doesn't even need to access any of the A's methods/fields, neither public nor protected/private. So it doesn't make sense. It would have made some sense otherwise, but at any rate it seems like it is worth re-thinking your problem and come up with a cleaner solution that does not need a hack like that. If, after a deep thought, you still believe you need it, you can do something like this:</p> <pre><code>#include &lt;cstdio&gt; template&lt;typename T&gt; typename T::member_type fcn(const T &amp; v) { return v.value_; } template&lt;class T&gt; class A { public: typedef T member_type; friend member_type fcn&lt; A&lt;T&gt; &gt;(const A&lt;T&gt; &amp;); A() : value_(1986) {} private: T value_; }; int main() { A&lt;int&gt; a; printf("The value is: %d\n", fcn(a)); } </code></pre> <p>Notable thing in the above example is that you need to de-couple a cross dependency and make your free-function not depend on a declaration of class <code>A</code>. If you still feel like you need that coupling, the following code works, too:</p> <pre><code>#include &lt;cstdio&gt; template &lt;typename T&gt; class A; template &lt;typename T&gt; typename A&lt;T&gt;::member_type fcn(const A&lt;T&gt; &amp; v) { return v.value_; } template &lt;typename T&gt; class A { public: typedef int member_type; friend member_type fcn&lt;T&gt;(const A&lt;T&gt; &amp;); A() : value_(1986) {} private: member_type value_; }; int main() { A&lt;void&gt; a; printf("The value is: %d\n", fcn(a)); } </code></pre> <p>Hope it helps. Good Luck!</p>
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    1. CO'fcn' does access 'A'`s fields. 'member_type' is in fact something like 'set<A*>'. Your example compiles, but once 'member_type' is in the parameters of 'fcn', I get 'error: template declaration of ‘typename...'. For example
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    2. CO@user1672572: Well, I believe your are very close to do whatever you want, and it should work as long as you don't forget typing `typename`. Otherwise... post a specific problem that you are having... or else it's really hard to guess to help you.
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    3. COFor example you code modified so that fcn takes an arg of 'member_type' as above, does not compile.
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