Why LoadLibrary Fail only when EXE is launched from the IDE ?

Question

Hi guys,

On Delphi 2009, on a new VCL project:

procedure TForm1.FormCreate(Sender: TObject);
var
    Handle: THandle;
begin
    Handle := loadlibrary('oci.dll');
    if Handle <> 0 then
    begin
        try
         ShowMessage('Success');
        finally
            FreeLibrary(Handle);
        end;
    end
    else
        ShowMessage('Fail');
end;

If i run the Exe from the IDE, it fails, if i run the EXE from the directory, just on double clicking on it it's a success !!??

Please tell me what I'm missing.

Thanks, Fred

EDIT: Launching the EXE via the IDE works with Delphi 7 !! WTf is the problem with D2009 ??

Answer 1

If the dependent DLL is in the same directory... make sure your startup directory is it.

This happens to me all the time in Visual Studio too...

Answer 2

The usual problem with LoadLibrary failing is that the required DLL is not in the DLL search path. It's possible that D2009 is not searching the same folders for some reason.

To make sure, you should get more details of the error, using something like...

ShowMessage(SysErrorMessage(GetLastError));

Try (even temporarily) placing "oci.dll" in the same directory as you project's .EXE, and try again.

Here are some things to check:

• Which directory is oci.dll located in?
• Is that directory included in the "PATH" environment variable? If not, try that.
• Have you maybe set an OVERRIDE for PATH in Delphi Tools/Options/Env variables screen?

Answer 3

I would suspect that the stand alone call works because the DLL happens to be in the current directory.

And, when started from the IDE, the current directory differs from the EXE directory.

Did you try to use the full path to the DLL (i.e., something like path from ParamStr(0) plus the DLL name)?