#include <windows.h>

      // MyDll_ReverseString -- Reverses the characters of a given string
      void __stdcall MyDll_ReverseString(LPSTR lpString)
      {
         _strrev(lpString);
      }

      // MyDLL_Rotate -- Returns bit rotation of 32-bit integer value
      int __stdcall MyDll_Rotate(int nVal, int nDirect, short iNumBits)
      {
         int nRet = 0;

         if((iNumBits < 1) || (iNumBits > 31))
            return nRet;

         switch(nDirect)
         {
         case 0:
            // Rotate nVal left by iNumBits
            nRet = (((nVal) << (iNumBits)) |
                    ((nVal) >> (32-(iNumBits))));
            break;
         case 1:
            // Rotate nVal right by iNumBits
            nRet = (((nVal) >> (iNumBits)) |
                    ((nVal) << (32-(iNumBits))));
            break;
         }

         return nRet;
      }

						

      LIBRARY TLBSamp
      DESCRIPTION 'Microsoft KB Sample DLL'
      EXPORTS
        MyDll_ReverseString
        MyDll_Rotate

						

      // This is the type library for TLBSamp.dll
      [
      // Use GUIDGEN.EXE to create the UUID that uniquely identifies
      // this library on the user's system. NOTE: This must be done!!
         uuid(F1B9E420-F306-11d1-996A-92FF02C40D32),
      // This helpstring defines how the library will appear in the
      // References dialog of VB.
         helpstring("KB Sample: Make your C DLL More Accessible"),
      // Assume standard English locale.
         lcid(0x0409),
      // Assign a version number to keep track of changes.
         version(1.0)
      ]
      library TLBSample
      {

      // Define an Enumeration to use in one of our functions.
      typedef enum tagRotateDirection
      {
         tlbRotateLeft=0,
         tlbRotateRight=1
      }RotateDirection;

      // Now define the module that will "declare" your C functions.
      [
         helpstring("Sample functions exported by TLibSamp.dll"),
         version(1.0),
      // Give the name of your DLL here.
         dllname("TLBSamp.dll")
      ]
      module MyDllFunctions
      {

         [
         // Add a description for your function that the developer can
         // read in the VB Object Browser.
            helpstring("Returns the reverse of a given string."),
         // Specify the actual DLL entry point for the function. Notice
         // the entry field is like the Alias keyword in a VB Declare
         // statement -- it allows you to specify a more friendly name
         // for your exported functions.
            entry("MyDll_ReverseString")
         ]
         // The [in], [out], and [in, out] keywords tell the Automation
         // client which direction parameters need to be passed. Some
         // calls can be optimized if a function only needs a parameter
         // to be passed one-way.
         void __stdcall ReverseString([in, out] LPSTR sMyString);

         [
            helpstring("Rotates a Long value in the given direction."),
            entry("MyDll_Rotate")
         ]
         // Besides specifying more friendly names, you can specify a more
         // friendly type for a parameter. Notice the Direction parameter
         // has been declared with our enumeration. This gives the VB
         // developer easy access to our constant values.
         int __stdcall BitRotate([in] int Value,
                                 [in] RotateDirection Direction,
                                 [in] short Bits);

      } // End of Module
      }; // End of Library

						

      Private Sub Command1_Click()
         Dim n1 As Long, n2 As Long, nTmp As Long
         Dim sTest As String, sMsg As String

         sTest = "Hello World!"
         n1 = 100

         ReverseString sTest
           sMsg = sTest & " | "
         ReverseString sTest
           sMsg = sMsg & sTest & vbCrLf

         nTmp = BitRotate(n1, tlbRotateLeft, 2)
         n2 = BitRotate(nTmp, tlbRotateRight, 2)
           sMsg = sMsg & Str$(n1) & " : " & Str$(nTmp) & " : " & Str$(n2)

         MsgBox sMsg
      End Sub