VB Forum / General 2 / February 2004

Hello all,

I am writing a small DLL of utility functions in VC++ 6 which must be
usable from VB 6. The functionality isn't particularly platform
specific, and I have a good deal of Mac programming experience in C++ -
and some in MS VB - just not enough in VC++. I'm having a problem with
setting up a function (from VB's viewpoint a Sub) to fill in a string -
I keep getting a Runtime Error 49 - Bad Calling convention. Here is an
extract of the code involved:

Declare Sub DisplayVersion Lib _
"D:\Clients\Henry\DLLv1\VBTest\CopyProtUtilityDLL.dll" _
(ByVal versionInfo As String)

   Dim sText As String
   ' Allocate string buffer
   sText = String$(256, vbNullChar)
   DisplayVersion sText      ' <-- error highlighted here

--------------

.h file:

#ifdef __cplusplus
  #ifndef __CPROTUTIL__
  #define __CPROTUTILLIB__ extern "C" __declspec(dllimport)
  #else
  #define __CPROTUTILLIB__ extern "C" __declspec(dllexport)
  #endif
....
#endif

__CPROTUTILLIB__ void DisplayVersion(LPSTR szVersionInfo);
  // returns copyright notice and version number

.cpp file:

// returns copyright notice and version number
__CPROTUTILLIB__ void DisplayVersion(LPSTR szVersionInfo)
  {
  sprintf(szVersionInfo, "%s", "Version 0.1 (c)2004");
  }

Please note that __CPROTUTIL__ is defined on the compiler command line
to force the export mode.

Thanks in advance - I'm sure this is going to be something dumb, but I
just can't see it!!

Frank Alviani