[Boost-users] boost::noncopyable doesn't work

Subject: [Boost-users] boost::noncopyable doesn't work
From: Maurer Philipp (philipp.maurer_at_[hidden])
Date: 2008-10-13 08:34:38

Hello,

 

I have a very special problem concerning boost::noncopyable under
Windows in a shared library. A class deriving from boost::noncopyable
becomes copyable. Strange ? Here is the example code. (Using Visual
Studio 2005, no sp, Windows XP):

 

1)      create one static lib with only TestClasses.hpp with the
following content in it: 
#include <boost/noncopyable.hpp> 

class INonCopyNormalClass: boost::noncopyable 
{ 
public: 
virtual INonCopyNormalClass* clone() = 0; 
}; 

2)      create one DLL (shared lib) with the following content: 

DLLMain.hpp: 
#include "../TestLib/TestClasses.hpp" 

# if defined(UNCOPYABLETESTDLL_EXPORTS) 
# define DLL_API __declspec(dllexport) 
# else 
# define DLL_API 
# endif 

class DLL_API AnotherNonNormalCopyClass: public INonCopyNormalClass 
{ 
}; 

class YetAnotherNonNormalCopyClass: public AnotherNonNormalCopyClass 
{ 
public: 
YetAnotherNonNormalCopyClass(); 

virtual INonCopyNormalClass* clone(); 
};

 

DLLMain.cpp: 
#include "DLLmain.hpp" 

YetAnotherNonNormalCopyClass::YetAnotherNonNormalCopyClass() 
{ 
} 

INonCopyNormalClass* YetAnotherNonNormalCopyClass::clone() 
{ 
return new YetAnotherNonNormalCopyClass(*this); 
} 

 

It is quite important that the DLL_API is defined properly !! This seems
to be the reason, that the code above compile, links and runs. This
should not be possible. The line return new
YetAnotherNonNormalCopyClass(*this); should not work. If DLL_API is
undefined or removed, you will get the correct error message and
compilation fails

 

 

ANY ideas ? SOMEONE ?

 

Thanks and best,

Philipp