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POTemplated "Listener" handler ambiguity problem
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  1. POTemplated "Listener" handler ambiguity problem
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    copied!<p>I'm using JUCE as a x-platform framework, and I'm using template listener classes to map button/combobox etc. callbacks to certain handler functions. Since the different widgets have their own callback function name, I use the following structure:</p> <pre><code>template&lt;typename Type, typename Widget&gt; class ListenerBase : public Widget::Listener { public: typedef void (Type::*TCallbackType)(void); protected: void notifyCallback(Widget* notifier) { ... } void addHandler(Widget* notifier, TCallbackType callback) { notifier-&gt;addListener(this); ... } }; template&lt;typename Type&gt; class ButtonListenerHandler : public ListenerBase&lt;Type, Button&gt; { protected: void buttonClicked(Button* btn) { notifyCallback(btn); } }; template&lt;typename Type&gt; class LabelListenerHandler : public ListenerBase&lt;Type, Label&gt; { protected: void labelTextChanged(Label* lbl) { notifyCallback(lbl); } }; </code></pre> <p>And it works fine, as long as I use only one of the handler specializations in my class. As soon as I use more than one, VC++ 2008 complains of ambiguity between the addHandler calls as if the compiler cannot distiguish between addHandler(Button*, ...) and addHandler(Label*, ...) !! These functions are of different prototypes due to being templatized, so I have no idea why the compiler is giving me a hard time. Ideas ?</p> <p>Edit due to requests:</p> <p>A class with different listeners may look like:</p> <pre><code>class MyClass : public ButtonListenerHandler&lt;MyClass&gt; , public LabelListenerHandler&lt;MyClass&gt; { ... void buttonHandlerFunction(); void labelHandlerFunction(); Button* m_btn; Label* m_label; }; </code></pre> <p>A where the error occurs:</p> <pre><code>MyClass::MyClass() { ... addHandler(m_btn, &amp;MyClass::buttonHandlerFunction); &lt;&lt;&lt; error addHandler(m_label, &amp;MyClass::labelHandlerFunction); &lt;&lt;&lt; error } </code></pre> <p>And the error is:</p> <pre><code>1&gt;MyClass.cpp(287) : error C2385: ambiguous access of 'addHandler' 1&gt; could be the 'addHandler' in base 'ListenerBase&lt;MyClass,juce::Button&gt;' 1&gt; or could be the 'addHandler' in base 'ListenerBase&lt;MyClass,juce::Label&gt;' </code></pre>
 

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