Yes, I know that.
implementation can be C++, of course).
That solves nothing since the class is still exported. What one
needs to do is define a C++ interface for the class and return
that from the C function (and the C++ interface should not
directly or indirectly reference any other C++ class that is not
in turn another C++ interface, should have no data nor static
members, and should not be derived from multiple other C++
interfaces). A C++ interface is a class containing only public
pure virtual methods. Also note you can't call operator delete
on the interface outside of your DLL, so you need to provide
another mechanism for disposing it (a global C function or
an interface emthod). Once you get there, you may realize
you've nearly reinvented COM, so you may go the extra step
and convert to a COM server...
--
=====================================
Alexander Nickolov
Microsoft MVP [VC], MCSD
email: agnickolov@mvps.org
MVP VC FAQ: http://vcfaq.mvps.org
=====================================
"Giovanni Dicanio" <giovanni.dicanio@invalid.com> wrote in message
news:uDZ60rdUIHA.3916@TK2MSFTNGP02.phx.gbl...
"2b|!2b==?" <user@domain.invalid> ha scritto nel messaggio
news:_9udncYmgLGlah_anZ2dnUVZ8uWdnZ2d@bt.com...
I have a DLL project that I need to export a data variable from. I have
defined the variable in a .cpp file in the project like this
//C++ file (DLL Project)
class MYPROJ_API data_type
{
//Impl here ...
};
You are exporting a C++ class.
Are you using the same compiler version to build the DLL and the client
of your DLL?
MYPROJ_API data_type exported_data;
Instead of exporting the class instance, you may try to export a global
function which returns a pointer to the class instance, something like
this:
data_type globalData;
MYPROJ_API data_type * GetExportedData(void)
{
return &globalData;
}
So the DLL client could call GetExportedData() to access the class
instance.
Giovanni