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POStrange error message when a class method is missing
 

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  1. POStrange error message when a class method is missing
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    <blockquote> <p><strong>Possible Duplicate:</strong><br> <a href="https://stackoverflow.com/questions/1095298/gcc-c-linker-errors-undefined-reference-to-vtable-for-xxx-undefined-referen">GCC C++ Linker errors: Undefined reference to &#39;vtable for XXX&#39;, Undefined reference to &#39;ClassName::ClassName()&#39;</a> </p> </blockquote> <p>I have been banging my head against a wall for a long time because of a strange ld error. So I reproduced it in a small test case to understand the issue.</p> <p>I declared a class and I derived another one in a header file:</p> <pre><code>class BaseClass { public: BaseClass(){}; virtual void func(){}; }; class DerivedClass: public BaseClass { public: DerivedClass(); void func(); }; </code></pre> <p>Then I defined the constructor but forgot to define <code>func</code> (voluntary here, but that actually what I did with a silly copy/paste...):</p> <pre><code>DerivedClass::DerivedClass(){ cout &lt;&lt; "Derived constructor" &lt;&lt; endl; } //void DerivedClass::func(){ // cout &lt;&lt; "Derived func" &lt;&lt; endl; //} </code></pre> <p>Then I get:</p> <blockquote> <p>undefined reference to `vtable for DerivedClass'</p> </blockquote> <p>Edit: And the message points the declaration of the consctructor!</p> <p>If I uncomment the definition of <code>func</code>, then I have no error. So my question: Why does the linker didn't tell me that the definition of <code>func</code> is missing?</p> <p>The solution might be obvious when you are experienced, but for a beginner like me it's not!</p> <p>Thanks for your help.</p>
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    1. USPlouff
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    1. COWhat compiler do you use?
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      1. USChristian Rau
    2. COPossible dup of http://stackoverflow.com/questions/1095298/gcc-c-linker-errors-undefined-reference-to-vtable-for-xxx-undefined-referen and http://stackoverflow.com/questions/7334269/undefined-reference-to-vtable-for-classname and http://stackoverflow.com/questions/5511973/undefined-reference-to-vtable any many others. Also, the question is answered in the GCC FAQ. http://gcc.gnu.org/faq.html#vtables
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      1. USRaymond Chen
    3. CO@RaymondChen: Even if a little bit rude, your answer with the link to GCC FAQ helped understanding the issue. I +1ed you!
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