singleton in a DLL loaded class

 PaulH <>
Mon, 25 Jun 2007 17:57:36 -0000
I have a class loaded from a DLL that I would like to implement as a
multi-threadable singleton. Unfortunately, I seem to still be getting
two distinct instances of this class. It is implemented as below.

The only funny thing I am doing is to load the DLL from two threads
simultaneously (thus the need for the singleton). But, according to
other posts I've read, the OS will point them both to the same
instance of the DLL so that only one thread actually loads the DLL.

Can anybody point out where I may be going wrong?


class SingletonClass : BaseClass
    static SingletonClass& Instance();
    //... Implement BaseClass functions
    static std::auto_ptr< SingletonClass > _theInstance;
    static Mutex* _m;

std::auto_ptr< SingletonClass > SingletonClass::_theInstance;
Mutex* SingletonClass::_m;

/*static*/ SingletonClass& SingletonClass::Instance()
    Mutex::Create( &_m );
    if( _theInstance.get() == NULL )
         _theInstance.reset( new SingletonClass() );
    return *_theInstance;

MY_API BaseClass* Create()
    return &SingletonClass::Instance();

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