Author: Tomas Rutkauskas

I'd like to have a background.wav file playing and once in a while have a short 
effects .wav sound play at the same time (without interrupting - stopping and 
restarting it - the background .wav).

Answer:

The Delphi code below plays two sounds concurrently under Win95. I think concurrent 
sound playing relies on the driver supporting multiple inputs, and I believe you 
could request if it has this capability before trying to play.


1   procedure TForm1.Button1Click(Sender: TObject);
2   begin
3     SendMCICommand('open waveaudio shareable');
4     SendMCICommand('play hickory.wav');
5     SendMCICommand('play greeting.wav');
6     SendMCICommand('close waveaudio');
7   end;
8   
9   procedure TForm1.SendMCICommand(Cmd: string);
10  var
11    RetVal: integer;
12    ErrMsg: array[0..254] of char;
13  begin
14    RetVal := mciSendString(StrAsPChar(Cmd), nil, 0, 0);
15    if RetVal <> 0 then
16    begin
17      {get message for returned value}
18      mciGetErrorString(RetVal, ErrMsg, 255);
19      MessageDlg(StrPas(ErrMsg), mtError, [mbOK], 0);
20    end;
21  end;
22  
23  function StrAsPChar(var S: OpenString): PChar;
24  {returns a PChar from a string}
25  begin
26    if Length(S) = High(S) then
27      dec(S[0]);
28    S[Ord(Length(s)) + 1] := #0;
29    Result := @S[1];
30  end;