'''Building Tcl DLL Extensions For Windows'''

Using Microsoft Visual C++ 6

   * Create a new win32 dynamic link library project and call it something nice, like ''tcldemo''. This is going to be our package name too.

   * Select an 'Empty DLL' on the next dialog.

   * Before you get going, make sure you have told Visual Studio about the Tcl headers and libraries. To do this, open Tools->Options->Directories and give the Tcl include directory in the includes box and the libraries in the libraries box.

   * Open up the Porject settings menu item for your new project and go to the C++ tab. Add USE_TCL_STUBS to the list of defined symbols and in the Link tab prepend tclstub83.lib to the list of libraries. (Adust the numerical suffix for your version of tcl).

   * Now we can write some code. Create a new C++ source file, called tcldemo.cpp and paste in the code below.

   * Build it. Ignore the whining about MSCVRT conflicts. You now have a DLL in either Debug/Release.

   * Fire up tclsh or better tkcon from the Debug or Release subdirectory under your project and issue
  load tcldemo.dll Tcldemo
  set tcldemo_version
  package require Tcldemo

   * You should get 0.1 printed twice!

----
The code:

 #include <windows.h>
 #include <tcl.h>
 
 #ifndef DECLSPEC_EXPORT
 #define DECLSPEC_EXPORT __declspec(dllexport)
 #endif // DECLSPEC_EXPORT
 
 BOOL APIENTRY
 DllMain(HANDLE hModule, DWORD dwReason, LPVOID lpReserved)
 {
     return TRUE;
 }
 
 EXTERN_C int DECLSPEC_EXPORT
 Tcldemo_Init(Tcl_Interp* interp)
 {
 #ifdef USE_TCL_STUBS
     Tcl_InitStubs(interp, "8.3", 0);
 #endif
     Tcl_Obj *version = Tcl_SetVar2Ex(interp, "tcldemo_version", NULL,
                                      Tcl_NewDoubleObj(0.1), TCL_LEAVE_ERR_MSG);
     if (version == NULL)
         return TCL_ERROR;
     int r = Tcl_PkgProvide(interp, "Tcldemo", Tcl_GetString(version));
     
     // Call Tcl_CreateObjCommand etc.
     
     return r;
 }
 
 EXTERN_C int DECLSPEC_EXPORT
 Tcldemo_SafeInit(Tcl_Interp* interp)
 {
     // We don't need to be specially safe so...
     return Tcldemo_Init(interp);
 }
----
This excellent piece of work was created and
put here by [Pat Thoyts].  Thanks Pat!