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Xoff · Guest

Hi,

I have a delphi (d2006) unit that calls mmsystem.playsound in its initialization block. I can use that unit in a simple project. However, if I make the same call in the initialization of a DLL (versus just a unit), and reference that DLL in my simple project, the program just hangs.

Has anybody experience/advice with that?
Thanks,
Xoff

Here is the code of the DLL:

library dllProject1;
uses
SysUtils,
Classes, MMSystem;
{$R *.res}

procedure testSound; stdcall;
begin
MMSystem.PlaySound('Minimize', 0, SND_ALIAS or SND_ASYNC or
SND_NODEFAULT or SND_NOWAIT);
end;

exports testSound;

begin
MMSystem.PlaySound('Minimize', 0, SND_ALIAS or SND_ASYNC or
SND_NODEFAULT or SND_NOWAIT);
end.

----------------------------------------------------------------
and the main program:
unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls,
Forms,
Dialogs, StdCtrls;

type
TForm1 = class(TForm)
Button1: TButton;
procedure Button1Click(Sender: TObject);
end;

procedure testSound; stdcall; external 'dllproject1.DLL';

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
testSound;
end;

initialization
//testSound;
end.

(and thanks to Riki Wiki for instructions on how to post here)

Guest

It is never a good idea to have code executed in the initialization section when working with a DLL: not for nothing it is a dynamic link LIBRARY.
You should explicitly call the function after loading the dll or call a specific initialize method for the dll

Xoff · Guest

Thanks Thaddy,

I have simplified the issue to its root cause. However, my issue is a little more complex: I have a third party unit that makes that call in the unit initializtion. This by itself is Ok. But I use that unit in the DLL I am writing, so the call to mmsystem is made then and I have little control over it.

I have access to the source of that third party unit, but I would like to avoid making such changes, as I may forget when I get a new version.

I will contact the vendor of that unit, but I was wondering if there was something special about that call or mmsystem in general. Or is it a Delphi thing?

Xoff
<thaddy@.not.thaddy.com> wrote: