Thanks a lot marc,
I was looking for that code that we used to prove this,
But couldn't find the damn thing...
Your 100% correct in what my problem is...
Id love any help to get this fixed... in fact I need
It fixed :(
I must port our companies server software to linux, and
I want to do that with freepascal. However we have made use
Of functions returning interfaces extensively and I can not
Change every instance of this in our software.
So if need be I can probably talk the company into "Sponsoring"
Someone (With the right experience) to fix this bug, should it
Come to that.
Jay Binks
-----Original Message-----
From: Administrator
Sent: Monday, 10 April 2006 8:16 PM
To: Jay Binks
Subject: FW: [fpc-devel] bug ID #4855
-------------------------------------------
From: [EMAIL PROTECTED] on behalf of Marc
Weustink[SMTP:[EMAIL PROTECTED]
Sent: Monday, 10 April 2006 8:15:31 PM
To: Administrator
Subject: Re: [fpc-devel] bug ID #4855
Auto forwarded by a Rule
Michael Van Canneyt wrote:
>
>
> On Mon, 10 Apr 2006, Peter Vreman wrote:
>
>>> Buys Regarding this bug #4855 I need to get it fixed..
>>>
>>>
>>>
>>> The issue like this... I have 2 parts to my system...
>>>
>>>
>>>
>>> The EXE ... and a DLL
>>>
>>>
>>>
>>> In the DLL I have an exported function that returns an Interface...
>>>
>>>
>>>
>>> Function dosomething( const aObjectInt : ISomeInt ) : ISomeOtherInt
>>>
>>>
>>>
>>> This fails and causes the application to die..
>>>
>>> However if I put the same function inside the EXE it works fine.
>>
>>
>> The DLL has it's own memory manager. The EXE can't access the memory
>> allocated in the DLL.
Maybe I can clearify some. Before this bug got submitted, I had a
converstaion with the submittor on IRC.
> Of course it can, when it gets a pointer ?
> It can't free it, of course, but that can be solved.
The dll is returning a COM interface, so it doesn't have to be freed in
the exe.
>
> Is the function called from a FPC application or a Delphi application
?
> If from delphi, try setting the 'stdcall' calling convention.
>
> I think some more explanation is in order so we can reproduce and
solve
> the problem.
The main problem is that a COM interface returned as a funtion result by
fpc is different than a result returned by delphi
All interface funtions are declared with stdcall.
I cannot recall if the calling exe was a delphi or fpc produced one, but
for this problem it doesn't really matter. What matters is mixing a
delphi/fpc exe with and fpc/delphi dll
the dll exports a function like
function SomeFunc: IUnknown; stdcall;
The exe imports this function. Assigning the function result results in
an AV (I tested this with a delphi dll and a fpc exe)
When the interface is passed as a var in a procedure call, it works OK.
Marc
=======================================================================
library DllProject;
{$IFDEF FPC}{$mode objfpc}{$H+}{$ENDIF}
uses
SysUtils,
Classes;
type
iTest = interface
['{B1473B32-DDB5-452C-86BE-9C4D85E68495}']
function dotest( const aIn : Integer ): Integer; stdcall;
end;
TTest = class(TInterfacedObject, iTest )
function dotest( const aIn : Integer ): Integer; stdcall;
end;
function TTest.dotest( const aIn : Integer ): Integer; stdcall;
begin
result := aIn + 1;
end;
Function test(): ITest; stdcall;
begin
result := TTest.create();
end;
procedure testproc(out T: ITest); stdcall;
begin
T := TTest.create();
end;
exports
test, testproc;
begin
end.
=======================================================================
program project1;
{$mode objfpc}{$H+}
uses
classes, windows;
type
ITest = interface
['{B1473B32-DDB5-452C-86BE-9C4D85E68495}']
function dotest( const aIn : Integer ): Integer; stdcall;
end;
TTest = Function(): ITest; stdcall;
TTestproc = procedure(out T: ITest); stdcall;
var
lLib: cardinal;
doTest: TTest;
doTestProc: TTestproc;
fTest: ITest;
begin
lLib := loadlibrary( 'dllProject.dll' );
pointer(doTest) := getprocaddress( lLib, 'test' );
pointer(doTestProc) := getprocaddress( lLib, 'testproc' );
if assigned( doTest ) then
begin
fTest := doTest();
WriteLN(FTest.dotest(1));
end;
if assigned(doTestProc) then
begin
doTestProc(fTest);
WriteLN(FTest.dotest(2));
end;
end.
_______________________________________________
fpc-devel maillist - fpc-devel@lists.freepascal.org
http://lists.freepascal.org/mailman/listinfo/fpc-devel
_______________________________________________
fpc-devel maillist - fpc-devel@lists.freepascal.org
http://lists.freepascal.org/mailman/listinfo/fpc-devel
