VB3 Using Visual Basic 3.0 to Play WAVE Files Stored in a DLL

• Microsoft Windows Software Development Kit (SDK) version 3.1
• Microsoft Visual Basic version 3.0

SUMMARY

By calling the necessary Windows API, a Visual Basic program can access and play wave files stored in a dynamic-link library (DLL). Generally, a DLL that contains only resources such as wave files is referred to as a resource-only library.

NOTE: Visual Basic 3.0 does not support the insertion of resources such as wave files into a DLL. A third-party tool such as the Microsoft C++ Compiler and its accompanying Resource Compiler are needed to accomplish this.

MORE INFORMATION

The following example shows how to create a resource-only library using Microsoft Visual C++ 1.5. For this example, the resource-only library contains the two wave files Ding.wav and Chimes.wav.

1. Create a text file and place the following lines of code in it:

      #include <windows.h>
      int FAR PASCAL LibMain(HANDLE hInstance, WORD wDataSeg, WORD wHeapSize,
      LPSTR lpszCmdLine)
      {
         if (wHeapSize > 0)
            UnlockData(0);
         return 1;
      }
   
   

2. Save the above file with the extension .c.

3. Create another file and place the following text in it (the lines below assume that both wave files are currently located in the c:\windows directory):

       Sound1 WAVE c:\windows\ding.wav
       Sound2 WAVE c:\windows\chimes.wav
   
   Save this file with the extension .rc. This will identify it as a
       resource file.
   
   From within Visual C++ version 1.5, click New on the Project menu to
       specify the name of your project. Then set the Project Type to "Windows
       dynamic-link library (.DLL)" and click OK.
   
   Use the Edit dialog box that appears next to add the .c and .rc files
       created in steps 1-3.
   
   On the Project menu, click Build. This will take the files created above
      and generate the resource-only library from them. This DLL contains the
      two wave files Ding.wav and Chimes.wav.
   

1. In the Visual Basic programs "General Declaration" section add the following code:

      Declare Function sndPlaySound Lib "mmsystem.dll" (ByVal lpRes As Any,
      ByVal wflags As Integer) As Integer
   
      Declare Function LoadLibrary Lib "kernel" (ByVal lpLibFileName As
      String) As Integer
   
      Declare Function FindResource Lib "kernel" (ByVal hInstance As Integer,
      ByVal lpname As String, ByVal lpType As Any) As Integer
   
      Declare Function LoadResource Lib "kernel" (ByVal hInstance As Integer,
      ByVal hResInfo As Integer) As Integer
   
      Declare Function LockResource Lib "kernel" (ByVal hResData As Integer)
      As Long
   
      Declare Function FreeResource Lib "kernel" (ByVal hResData As Integer)
      As Integer
   
      Declare Sub FreeLibrary Lib "kernel" (ByVal hInstance As Integer)
   
      Const SND_MEMORY = 4
   
   

2. In a subroutine add the following Visual Basic code. This is the code that actually opens the DLL and plays the Ding.wav file:

   Dim hInstance As Integer Dim hResInfo As Integer Dim hRes As Integer Dim lpRes As Long Dim iReturn As Integer

   hInstance = LoadLibrary("c:\wavedll.dll") hResInfo = FindResource(hInstance, "Sound1", "WAVE") hRes = LoadResource(hInstance, hResInfo) lpRes = LockResource(hRes) iReturnVal = sndPlaySound(lpRes, SND_MEMORY)

   iReturnVal = FreeResource(hRes) FreeLibrary(hInstance)

3. You can then call the subroutine the code in step 9 was added to whenever you want the sound played.