From: Greg Clayton (Greg.Clayton_at_[hidden])
Date: 2004-03-10 13:37:07
I am trying to do explicitly instantiate specific shared_ptr class for export from a Win32 DLL (currently with MSVC6, and eventually in VS2003). I have followed the Win32 rules found at:
and have something like:
// Provide the storage class specifier (extern for an .exe file, null
// for DLL) and the __declspec specifier (dllimport for .an .exe file,
// dllexport for DLL).
// You must define EXP_STL when compiling the DLL.
// You can now use this header file in both the .exe file and DLL - a
// much safer means of using common declarations than two different
// header files.
#ifdef EXP_STL
# define DECLSPECIFIER __declspec(dllexport)
# define EXPIMP_TEMPLATE
#else
# define DECLSPECIFIER __declspec(dllimport)
# define EXPIMP_TEMPLATE extern
#endif
EXPIMP_TEMPLATE template class DECLSPECIFIER boost::shared_ptr<SomeClass>;
When I look through the exports, some needed class functions seem to be missing from the DLL, and linking fails. Most notable are:
void boost::shared_ptr<SomeClass>::reset(SomeClass*)
This function is declared in the shared_ptr header file as:
template<class Y> void reset(Y * p);
The reset function which does not take an argument is in the export list which is defined as:
void reset(); // never throws
And if I have a forward declaration of class followed by explicit instantiation, such as found below:
class SomeClass;
EXPIMP_TEMPLATE template class DECLSPECIFIER boost::shared_ptr<SomeClass>;
The constructor that takes a class pointer is not generated:
public: __thiscall boost::shared_ptr<class SomeClass>::shared_ptr<class SomeClass>(class SomeClass *)
which is declared as:
template<class Y> explicit shared_ptr(Y * p);
Do I need to do extra explicit instantiations for the class members whose declarations start with "template<class Y>"? If so how does this syntax work?
Any help or tips would be most appreciated.
Greg Clayton