What decides whether RegisterTypeLib writes to win32 or win64?

I am working with two ATL-based COM projects.

The both implement DllRegisterServer as just

STDAPI DllRegisterServer(void)
{
  // registers object, typelib and all interfaces in typelib
  return _Module.RegisterServer(TRUE);
}

which ends up calling

::RegisterTypeLib(pTypeLib, bstrPath, szDir);

in atlbase.h:6516.

But for some reason this call makes one of the projects create

HKEY_CLASSES_ROOT\TypeLib\<guid>\<version>\0\win64

when registered using regsvr32.exe on Windows 7 32 bit.

The other project correctly creates

HKEY_CLASSES_ROOT\TypeLib\<guid>\<version>\0\win32

Where should I start looking to find and fix this behavior?

Solution

It is strongly possible, that the typelibrary is targeted for the win64 platform. Check the typelibary's attributes. One may access them via ITypeLib::GetLibAttr:

ITypeLib::GetLibAttr(TLIBATTR **ppTLibAttr)

The TLIBATTR structure has a field of type SYSKIND. It contains a value which indicates the platform.

typedef enum tagSYSKIND {
  SYS_WIN16   = 0,
  SYS_WIN32   = ( SYS_WIN16 + 1 ),
  SYS_MAC     = ( SYS_WIN32 + 1 ),
  SYS_WIN64   = ( SYS_MAC + 1 ) 
} SYSKIND;

I hope this will help you to solve the problem