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    <p><strong>myclass.h</strong></p> <pre><code>#ifndef __MYCLASS_H__ #define __MYCLASS_H__ class MyClass { public: MyClass(); /* use virtual otherwise linker will try to perform static linkage */ virtual void DoSomething(); private: int x; }; #endif </code></pre> <p><strong>myclass.cc</strong></p> <pre><code>#include "myclass.h" #include &lt;iostream&gt; using namespace std; extern "C" MyClass* create_object() { return new MyClass; } extern "C" void destroy_object( MyClass* object ) { delete object; } MyClass::MyClass() { x = 20; } void MyClass::DoSomething() { cout&lt;&lt;x&lt;&lt;endl; } </code></pre> <p><strong>class_user.cc</strong></p> <pre><code>#include &lt;dlfcn.h&gt; #include &lt;iostream&gt; #include "myclass.h" using namespace std; int main(int argc, char **argv) { /* on Linux, use "./myclass.so" */ void* handle = dlopen("myclass.so", RTLD_LAZY); MyClass* (*create)(); void (*destroy)(MyClass*); create = (MyClass* (*)())dlsym(handle, "create_object"); destroy = (void (*)(MyClass*))dlsym(handle, "destroy_object"); MyClass* myClass = (MyClass*)create(); myClass-&gt;DoSomething(); destroy( myClass ); } </code></pre> <p>On Mac OS X, compile with:</p> <pre><code>g++ -dynamiclib -flat_namespace myclass.cc -o myclass.so g++ class_user.cc -o class_user </code></pre> <p>On Linux, compile with:</p> <pre><code>g++ -fPIC -shared myclass.cc -o myclass.so g++ class_user.cc -ldl -o class_user </code></pre> <p>If this were for a plugin system, you would use MyClass as a base class and define all the required functions virtual. The plugin author would then derive from MyClass, override the virtuals and implement <code>create_object</code> and <code>destroy_object</code>. Your main application would not need to be changed in any way.</p>
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    1. COI'm in the process of trying this, but just have one question. Is it strictly necessary to use void*, or could the create_object function return MyClass* instead? I'm not asking you to change this for me, I'd just like to know if there's a reason to use one over the other.
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    2. COIt can be MyClass*, no reason for it to be void*, I've updated it.
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    3. COThanks, I tried this and it worked as is on Linux from the command line (once I made the change you suggested in the code comments). I appreciate your time.
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