"Joe Hoggood" <jhoggood@jhoggood.com> wrote in message
news:vrif4q5ldsaec5@corp.supernews.com...
> I am trying to call a VC++.NET exported function (Win32 DLL) in VB6. When
I
> try to call this exported function from VB6 I get the following error:
Error
> 453: Can't find DLL entry point xx in yy.dll
>
> VC++.NET cpp/h source:
>
> // Win32DLL.cpp : Defines the entry point for the DLL application.
> #include "stdafx.h"
>
> #include "Win32DLL.h"
>
> BOOL APIENTRY DllMain(
>
> HANDLE hModule,
>
> DWORD ul_reason_for_call,
>
> LPVOID lpReserved
>
> )
>
> {
>
> switch (ul_reason_for_call)
>
> {
>
> case DLL_PROCESS_ATTACH:
>
> case DLL_THREAD_ATTACH:
>
> case DLL_THREAD_DETACH:
>
> case DLL_PROCESS_DETACH:
>
> break;
>
> }
>
>
> return TRUE;
>
> }
>
> // This is an example of an exported variable
>
> WIN32DLL_API public int nWin32DLL = 0;
>
> // This is an example of an exported function.
>
> WIN32DLL_API public int fnWin32DLL(int varIn)
>
> {
>
> int varOut;
>
> varOut = varIn;
>
> return varOut;
>
> }
>
> // This is the constructor of a class that has been exported. See
Win32DLL.h
> for the class definition
>
> CWin32DLL::CWin32DLL()
>
> {
>
> return;
>
> }
>
>
> #ifdef WIN32DLL_EXPORTS
>
> #define WIN32DLL_API __declspec(dllexport)
>
> #else
>
> #define WIN32DLL_API __declspec(dllimport)
>
> #endif
>
> // This class is exported from the Win32DLL.dll
>
> class WIN32DLL_API CWin32DLL
>
> {
>
> public:
>
> CWin32DLL(void);
>
> // TODO: add your methods here.
>
> };
>
> extern WIN32DLL_API int nWin32DLL;
>
> WIN32DLL_API int fnWin32DLL(int varIn);
>
>
>
> Here's my VB6 tester code:
>
> 'Set up global declarations and declare functions.
> Declare Function fnWin32DLL Lib
> "C:\jhoggood\Applications\CommonC\BuildFiles\Win32DLL\Debug\Win32DLL.dll"
> (ByVal varIn As Integer) As Integer
>
> Public Function DoExternFunc(myInputVarA As Integer) As Integer
> ' Call external function
> DoExternFunc = fnWin32DLL(myInputVarA)
> Debug.Print myResult
> End Function
>
>
> Private Sub cmdCompute_Click()
> Dim x As Integer
> x = DoExternFunc(4)
> txtInputVarA.Text = x
> End Sub
>
>
>
>
>
>
>
>

"Ronald Laeremans [MSFT]" <ronaldl@online.microsoft.com> wrote in message
news:ezvKGMVrDHA.2476@tk2msftngp13.phx.gbl...
> Make sure this is in an extern "C" block.
>
> Have you looked at the DLL exports using dumpbin or depends or some other
> tool?
>
> Ronald Laeremans
> Visual C++ team
>
> "Joe Hoggood" <jhoggood@jhoggood.com> wrote in message
> news:vrif4q5ldsaec5@corp.supernews.com...
> > I am trying to call a VC++.NET exported function (Win32 DLL) in VB6.
When
> I
> > try to call this exported function from VB6 I get the following error:
> Error
> > 453: Can't find DLL entry point xx in yy.dll
> >
> > VC++.NET cpp/h source:
> >
> > // Win32DLL.cpp : Defines the entry point for the DLL application.
> > #include "stdafx.h"
> >
> > #include "Win32DLL.h"
> >
> > BOOL APIENTRY DllMain(
> >
> > HANDLE hModule,
> >
> > DWORD ul_reason_for_call,
> >
> > LPVOID lpReserved
> >
> > )
> >
> > {
> >
> > switch (ul_reason_for_call)
> >
> > {
> >
> > case DLL_PROCESS_ATTACH:
> >
> > case DLL_THREAD_ATTACH:
> >
> > case DLL_THREAD_DETACH:
> >
> > case DLL_PROCESS_DETACH:
> >
> > break;
> >
> > }
> >
> >
> > return TRUE;
> >
> > }
> >
> > // This is an example of an exported variable
> >
> > WIN32DLL_API public int nWin32DLL = 0;
> >
> > // This is an example of an exported function.
> >
> > WIN32DLL_API public int fnWin32DLL(int varIn)
> >
> > {
> >
> > int varOut;
> >
> > varOut = varIn;
> >
> > return varOut;
> >
> > }
> >
> > // This is the constructor of a class that has been exported. See
> Win32DLL.h
> > for the class definition
> >
> > CWin32DLL::CWin32DLL()
> >
> > {
> >
> > return;
> >
> > }
> >
> >
> > #ifdef WIN32DLL_EXPORTS
> >
> > #define WIN32DLL_API __declspec(dllexport)
> >
> > #else
> >
> > #define WIN32DLL_API __declspec(dllimport)
> >
> > #endif
> >
> > // This class is exported from the Win32DLL.dll
> >
> > class WIN32DLL_API CWin32DLL
> >
> > {
> >
> > public:
> >
> > CWin32DLL(void);
> >
> > // TODO: add your methods here.
> >
> > };
> >
> > extern WIN32DLL_API int nWin32DLL;
> >
> > WIN32DLL_API int fnWin32DLL(int varIn);
> >
> >
> >
> > Here's my VB6 tester code:
> >
> > 'Set up global declarations and declare functions.
> > Declare Function fnWin32DLL Lib
> >
"C:\jhoggood\Applications\CommonC\BuildFiles\Win32DLL\Debug\Win32DLL.dll"
> > (ByVal varIn As Integer) As Integer
> >
> > Public Function DoExternFunc(myInputVarA As Integer) As Integer
> > ' Call external function
> > DoExternFunc = fnWin32DLL(myInputVarA)
> > Debug.Print myResult
> > End Function
> >
> >
> > Private Sub cmdCompute_Click()
> > Dim x As Integer
> > x = DoExternFunc(4)
> > txtInputVarA.Text = x
> > End Sub
> >
> >
> >
> >
> >
> >
> >
> >
>
>

"Joe Hoggood" <jhoggood@jhoggood.com> wrote in message
news:vrkrlinu2eia24@corp.supernews.com...
> Turns out this is a VB6 bug where you must run the application from an EXE
> (File/Make EXE) otherwise you will get the following error:
>
> Run-time error: '49' Bad DLL calling convention
>
>
>
> "Joe Hoggood" <jhoggood@jhoggood.com> wrote in message
> news:vriggp8th32h4b@corp.supernews.com...
> > Yes, I have looked using Dependency Walker V2.1 and the exported
function
> > "fnWin32DLL" is there. What should my extern declarations look like in
the
> > h/cpp files?
> >
> > Thanks!
> >
> >
> >
> >
> > "Ronald Laeremans [MSFT]" <ronaldl@online.microsoft.com> wrote in
message
> > news:ezvKGMVrDHA.2476@tk2msftngp13.phx.gbl...
> > > Make sure this is in an extern "C" block.
> > >
> > > Have you looked at the DLL exports using dumpbin or depends or some
> other
> > > tool?
> > >
> > > Ronald Laeremans
> > > Visual C++ team
> > >
> > > "Joe Hoggood" <jhoggood@jhoggood.com> wrote in message
> > > news:vrif4q5ldsaec5@corp.supernews.com...
> > > > I am trying to call a VC++.NET exported function (Win32 DLL) in VB6.
> > When
> > > I
> > > > try to call this exported function from VB6 I get the following
error:
> > > Error
> > > > 453: Can't find DLL entry point xx in yy.dll
> > > >
> > > > VC++.NET cpp/h source:
> > > >
> > > > // Win32DLL.cpp : Defines the entry point for the DLL application.
> > > > #include "stdafx.h"
> > > >
> > > > #include "Win32DLL.h"
> > > >
> > > > BOOL APIENTRY DllMain(
> > > >
> > > > HANDLE hModule,
> > > >
> > > > DWORD ul_reason_for_call,
> > > >
> > > > LPVOID lpReserved
> > > >
> > > > )
> > > >
> > > > {
> > > >
> > > > switch (ul_reason_for_call)
> > > >
> > > > {
> > > >
> > > > case DLL_PROCESS_ATTACH:
> > > >
> > > > case DLL_THREAD_ATTACH:
> > > >
> > > > case DLL_THREAD_DETACH:
> > > >
> > > > case DLL_PROCESS_DETACH:
> > > >
> > > > break;
> > > >
> > > > }
> > > >
> > > >
> > > > return TRUE;
> > > >
> > > > }
> > > >
> > > > // This is an example of an exported variable
> > > >
> > > > WIN32DLL_API public int nWin32DLL = 0;
> > > >
> > > > // This is an example of an exported function.
> > > >
> > > > WIN32DLL_API public int fnWin32DLL(int varIn)
> > > >
> > > > {
> > > >
> > > > int varOut;
> > > >
> > > > varOut = varIn;
> > > >
> > > > return varOut;
> > > >
> > > > }
> > > >
> > > > // This is the constructor of a class that has been exported. See
> > > Win32DLL.h
> > > > for the class definition
> > > >
> > > > CWin32DLL::CWin32DLL()
> > > >
> > > > {
> > > >
> > > > return;
> > > >
> > > > }
> > > >
> > > >
> > > > #ifdef WIN32DLL_EXPORTS
> > > >
> > > > #define WIN32DLL_API __declspec(dllexport)
> > > >
> > > > #else
> > > >
> > > > #define WIN32DLL_API __declspec(dllimport)
> > > >
> > > > #endif
> > > >
> > > > // This class is exported from the Win32DLL.dll
> > > >
> > > > class WIN32DLL_API CWin32DLL
> > > >
> > > > {
> > > >
> > > > public:
> > > >
> > > > CWin32DLL(void);
> > > >
> > > > // TODO: add your methods here.
> > > >
> > > > };
> > > >
> > > > extern WIN32DLL_API int nWin32DLL;
> > > >
> > > > WIN32DLL_API int fnWin32DLL(int varIn);
> > > >
> > > >
> > > >
> > > > Here's my VB6 tester code:
> > > >
> > > > 'Set up global declarations and declare functions.
> > > > Declare Function fnWin32DLL Lib
> > > >
> >
"C:\jhoggood\Applications\CommonC\BuildFiles\Win32DLL\Debug\Win32DLL.dll"
> > > > (ByVal varIn As Integer) As Integer
> > > >
> > > > Public Function DoExternFunc(myInputVarA As Integer) As Integer
> > > > ' Call external function
> > > > DoExternFunc = fnWin32DLL(myInputVarA)
> > > > Debug.Print myResult
> > > > End Function
> > > >
> > > >
> > > > Private Sub cmdCompute_Click()
> > > > Dim x As Integer
> > > > x = DoExternFunc(4)
> > > > txtInputVarA.Text = x
> > > > End Sub
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > >
> > >
> >
> >
>
>
>

"Joe Hoggood" <jhoggood@jhoggood.com> wrote in message
news:vriggp8th32h4b@corp.supernews.com...
> Yes, I have looked using Dependency Walker V2.1 and the exported function
> "fnWin32DLL" is there. What should my extern declarations look like in the
> h/cpp files?
>
> Thanks!
>
>
>
>
> "Ronald Laeremans [MSFT]" <ronaldl@online.microsoft.com> wrote in message
> news:ezvKGMVrDHA.2476@tk2msftngp13.phx.gbl...
> > Make sure this is in an extern "C" block.
> >
> > Have you looked at the DLL exports using dumpbin or depends or some
other
> > tool?
> >
> > Ronald Laeremans
> > Visual C++ team
> >
> > "Joe Hoggood" <jhoggood@jhoggood.com> wrote in message
> > news:vrif4q5ldsaec5@corp.supernews.com...
> > > I am trying to call a VC++.NET exported function (Win32 DLL) in VB6.
> When
> > I
> > > try to call this exported function from VB6 I get the following error:
> > Error
> > > 453: Can't find DLL entry point xx in yy.dll
> > >
> > > VC++.NET cpp/h source:
> > >
> > > // Win32DLL.cpp : Defines the entry point for the DLL application.
> > > #include "stdafx.h"
> > >
> > > #include "Win32DLL.h"
> > >
> > > BOOL APIENTRY DllMain(
> > >
> > > HANDLE hModule,
> > >
> > > DWORD ul_reason_for_call,
> > >
> > > LPVOID lpReserved
> > >
> > > )
> > >
> > > {
> > >
> > > switch (ul_reason_for_call)
> > >
> > > {
> > >
> > > case DLL_PROCESS_ATTACH:
> > >
> > > case DLL_THREAD_ATTACH:
> > >
> > > case DLL_THREAD_DETACH:
> > >
> > > case DLL_PROCESS_DETACH:
> > >
> > > break;
> > >
> > > }
> > >
> > >
> > > return TRUE;
> > >
> > > }
> > >
> > > // This is an example of an exported variable
> > >
> > > WIN32DLL_API public int nWin32DLL = 0;
> > >
> > > // This is an example of an exported function.
> > >
> > > WIN32DLL_API public int fnWin32DLL(int varIn)
> > >
> > > {
> > >
> > > int varOut;
> > >
> > > varOut = varIn;
> > >
> > > return varOut;
> > >
> > > }
> > >
> > > // This is the constructor of a class that has been exported. See
> > Win32DLL.h
> > > for the class definition
> > >
> > > CWin32DLL::CWin32DLL()
> > >
> > > {
> > >
> > > return;
> > >
> > > }
> > >
> > >
> > > #ifdef WIN32DLL_EXPORTS
> > >
> > > #define WIN32DLL_API __declspec(dllexport)
> > >
> > > #else
> > >
> > > #define WIN32DLL_API __declspec(dllimport)
> > >
> > > #endif
> > >
> > > // This class is exported from the Win32DLL.dll
> > >
> > > class WIN32DLL_API CWin32DLL
> > >
> > > {
> > >
> > > public:
> > >
> > > CWin32DLL(void);
> > >
> > > // TODO: add your methods here.
> > >
> > > };
> > >
> > > extern WIN32DLL_API int nWin32DLL;
> > >
> > > WIN32DLL_API int fnWin32DLL(int varIn);
> > >
> > >
> > >
> > > Here's my VB6 tester code:
> > >
> > > 'Set up global declarations and declare functions.
> > > Declare Function fnWin32DLL Lib
> > >
> "C:\jhoggood\Applications\CommonC\BuildFiles\Win32DLL\Debug\Win32DLL.dll"
> > > (ByVal varIn As Integer) As Integer
> > >
> > > Public Function DoExternFunc(myInputVarA As Integer) As Integer
> > > ' Call external function
> > > DoExternFunc = fnWin32DLL(myInputVarA)
> > > Debug.Print myResult
> > > End Function
> > >
> > >
> > > Private Sub cmdCompute_Click()
> > > Dim x As Integer
> > > x = DoExternFunc(4)
> > > txtInputVarA.Text = x
> > > End Sub
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> >
> >
>
>

>Turns out this is a VB6 bug where you must run the application from an EXE
>(File/Make EXE) otherwise you will get the following error:
>
>Run-time error: '49' Bad DLL calling convention