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can cppbuilder invoke microsoft visuall cpp class which incl

 
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Wen
Guest
PostPosted: Fri Aug 12, 2005 2:27 am    Post subject: can cppbuilder invoke microsoft visuall cpp class which incl Reply with quote


as i know, cppbuilder can invoke extern "C" __stdcall api of vc dll, but i
wanna invoke c++ class of vc dll?

is there any way to this goal?

any help would be greatly appreciated.

with my best regards,
Wen


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Jonathan Benedicto
Guest
PostPosted: Fri Aug 12, 2005 3:54 am    Post subject: Re: can cppbuilder invoke microsoft visuall cpp class which Reply with quote


"Wen" <wenming_hu2002 (AT) hotmail (DOT) com> wrote

Quote:
as i know, cppbuilder can invoke extern "C" __stdcall api of vc dll, but
i
wanna invoke c++ class of vc dll?

is there any way to this goal?

AFAIK, you'd have to write your class in the dll like this:

#ifdef IS_THE_DLL
#define CLASS_DECLARATION __declspec(dllexport)
#else
#define CLASS_DECLARATION __declspec(dllimport)
#endif

class CLASS_DECLARATION MyClass
{
....

Then you'd need to write a function like this inside the dll:

extern "C" __declspec(dllexport) MyClass* CreateMyClass() { return new
MyClass; }

Finally define IS_THE_DLL when building the DLL, otherwise undef it for
using the DLL in BCB.

HTH

Jonathan



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Wen
Guest
PostPosted: Fri Aug 12, 2005 4:24 am    Post subject: Re: can cppbuilder invoke microsoft visuall cpp class which Reply with quote



"Jonathan Benedicto" <incorrect (AT) no (DOT) server>
:42fc1d69 (AT) newsgroups (DOT) borland.com...
Quote:
"Wen" <wenming_hu2002 (AT) hotmail (DOT) com> wrote in message
news:42fc0906 (AT) newsgroups (DOT) borland.com...
as i know, cppbuilder can invoke extern "C" __stdcall api of vc dll, but
i
wanna invoke c++ class of vc dll?

is there any way to this goal?

AFAIK, you'd have to write your class in the dll like this:

#ifdef IS_THE_DLL
#define CLASS_DECLARATION __declspec(dllexport)
#else
#define CLASS_DECLARATION __declspec(dllimport)
#endif

class CLASS_DECLARATION MyClass
{
...

Then you'd need to write a function like this inside the dll:

extern "C" __declspec(dllexport) MyClass* CreateMyClass() { return new
MyClass; }

Finally define IS_THE_DLL when building the DLL, otherwise undef it for
using the DLL in BCB.

why do i need write extern "C" __declspec(dllexport) MyClass*
CreateMyClass() { return new MyClass; }?
so how do i invoke the C++ class of vc dll? do the same things as invoking
C++ class of vc dll in vc?

Thank you
Quote:

HTH

Jonathan




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Remy Lebeau (TeamB)
Guest
PostPosted: Fri Aug 12, 2005 8:22 am    Post subject: Re: can cppbuilder invoke microsoft visuall cpp class which Reply with quote

"Wen" <wenming_hu2002 (AT) hotmail (DOT) com> wrote


Quote:
why do i need write extern "C" __declspec(dllexport)
MyClass* CreateMyClass() { return new MyClass; }?

The point Jonathan is trying to make is that you cannot directly use vc++
classes from Borland compilers, so you have to flatten the access into
C-style functions that do the work for you, and then you can access the
functions instead.

Quote:
so how do i invoke the C++ class of vc dll?

You cannot.


Gambit



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