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POClass has virtual method but non virtual destructor C++
 

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  1. POClass has virtual method but non virtual destructor C++
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    <blockquote> <p><strong>Possible Duplicate:</strong><br> <a href="https://stackoverflow.com/questions/127426/gnu-compiler-warning-class-has-virtual-functions-but-non-virtual-destructor">GNU compiler warning &ldquo;class has virtual functions but non-virtual destructor&rdquo;</a> </p> </blockquote> <p>I am writing an interface for two classes and I get the warning in the title. Here's the code:</p> <pre><code>class GenericSymbolGenerator { protected: // &lt;== ok ~GenericSymbolGenerator(void) {} public: virtual GenericSymbolTableCollection* generateSymbolTableCollection(GenericSymbolTableCollection *gst) = 0; GenericSymbolGenerator(void) {} // ~GenericSymbolGenerator(void) {} // &lt;== warning if used }; class PascalPredefinedSymbolGenerator : public GenericSymbolGenerator { protected: ~PascalPredefinedSymbolGenerator(void) {} // &lt;== ok public: GenericSymbolTableCollection* generateSymbolTableCollection(GenericSymbolTableCollection *pst); // initializes *pst PascalPredefinedSymbolGenerator(void) {} // ~PascalPredefinedSymbolGenerator(void) {} &lt;== warning if used }; class PascalSymbolGenerator : public GenericSymbolGenerator { protected: ~PascalSymbolGenerator(void) {} // &lt;== ok public: GenericSymbolTableCollection* generateSymbolTableCollection(GenericSymbolTableCollection *st); // initializes st PascalSymbolGenerator(void) {} // ~PascalSymbolGenerator(void) {} // &lt;== warning if used }; </code></pre> <p>As long as the constructor/destructor is void there is no issue in declaring the destructor as protected. The problem arises when the class makes use of the heap(the destructor being declared as protected there is no way of freeing the class from the "outside" making the object "indestructible"). Is there a more convenient approach(aside from going public all the way)?</p>
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    1. COWhy do you want to make the destructor protected?
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      1. USTimo Geusch
    2. COIt is only a scenario in case the interface must be completely restricted to the user.
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    3. CO> Can you clarify your problem even further? > Why do you want a public constructor & a protected destructor? > As the destructor should be virtual .. so that when you destroy the Object of the child class, it calls the destructors of the base classes.
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      1. USMahmoud Aladdin
 

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