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"Le Doute" <ledoute@sceptiques.qc.ca> wrote:

>Hi,
>
>I'm a certainly not an expert in object pascal, and I've just ran into some
>trouble:
>
>I need to convert one of my app (some kind of "utility") into a DLL to sell
>what it does without selling its source (!). I can convert my app to a DLL
>that would require only few inputs.
>
>I need to pass to the DLL some strings. But ObjPascal has its own way to
>manage strings which are not compatible with other compilers.  Using
>ShareMem as Borland recommands isn't really what I want.
>
>I have no experience with pointers so I would need some help:
>
>My DLL needs to receive a string.
>
>How can I export this string to the DLL through a pointer, and how do I
>reconvert the pointer to a string inside my DLL? And "vice-versa", how can I
>import a DLL output through a pointer.
>
>For now, my code would look like this:
>
>procedure ProcedureInsideTheDLL (Input:String; Output:String);
>
>
This procedure should be on the DLL-side: (It reads a string from a
indexed string resource of the dll. (Resource,res))

Main file:

library dllstr;
uses
  Loadres in 'LOADRES.PAS';
exports
  GetResource              index 1;

{$R *.RES}
{$R resource.res}
begin
end.

(Unit that actually contain the procedure)

UNIT loadres;

INTERFACE
var
 buffer:array[0..255] of char;

Procedure Getresource(i:integer;P:PChar); export;

IMPLEMENTATION
uses sysutils,winprocs;

Procedure Getresource(i:integer; P:PChar);
Begin
  LoadString(HInstance,i,Buffer,Sizeof(Buffer));
  StrCopy(P,buffer);
end;

end.

This should go on the calling side:

type
  Getresproc = procedure(i:integer;P:Pchar);
var
  Getres        : getresproc;

Function LoadDLL(dllname:string):boolean;
Var
  buffer:array[0..255]of char;
  entrypoint:TFarproc;

Begin
  entrypoint := nil;
  StrPCopy(buffer,dllname);
  DLLHandle:=LoadLibrary(buffer);
  If DLLHandle < 22 then
    result :=False
  else begin
    StrPCopy(buffer,'Getresource');
    EntryPoint:=GetProcAddress(DLLHandle,buffer);
    If Entrypoint=nil then
      result :=False
    else begin
      @Getres:=EntryPoint;
      result:=true;
    end;
  end;
end;

Hope this helps.