Threads: Access violation on COM-Server destroing

Alex Penner

Delphi Developer

Sun, 09 Nov 2003 16:58:10 GMT

Threads: Access violation on COM-Server destroing

Hello all,

I'll try to explain, what I'm trying to do:

My program uses COM-Server - say Foo1
From the thread I'm creating (this is only one thread I'm creating) I want
to initialize another Com-Server Foo2 using Foo1.Connect function.
The idea is that the Foo2 Server will be inialized only once because of
performance reasons. (...and it has to be initialised in this thread).

procedure TThread.Execute;
begin
...
Foo1.Connect;
...
end;

function Foo1.Connect: boolean;
begin
if Connected then Exit;

try
ComInit := Succeeded(CoInitializeEx (nil, COINIT_APARTMENTTHREADED));

FFoo2 := CoFoo2.Create;
FFoo2.Connect;
Connected := True;

except
on E: Exception do
begin
.....
end;
end;
end;

That works so far. After that the thread goes terminated.
On Exit I want to destroy Foo2 in that way:

destructor Main.Destroy;
begin
Foo1 := nil;
inherited;
end;

destrucor Foo1.Destroy;
begin
Foo1.Disconnect;
inherited;
end;

function Foo1.Disconnect;
begin
if Connected then
begin

if FFoo2.IsConnected then
FFoo2.Disconnect;

try
FFoo2 := nil;
// I get access violation here
// I even cannot catch it with this try...except block.

except
on E: Exception do
ShowMessage(E.Message);
end;

if ComInit then CoUninitialize;
end;

inherited;
end;

Any Ideas?
Alex

Binh L

Delphi Developer

Mon, 10 Nov 2003 09:40:24 GMT

Re:Threads: Access violation on COM-Server destroing

Can you show your actual code that compiles? This code looks like its
inconsitent and its hard to determine which is which.

--
have fun
Binh Ly
www.techvanguards.com

Quote

"Alex Penner" <a...@c-studios.de> wrote in message

news:3b0b7bd6$1_1@dnews...

Quote

> procedure TThread.Execute;
> begin
> ...
> Foo1.Connect;
> ...
> end;

> function Foo1.Connect: boolean;
> begin
> if Connected then Exit;

> try
> ComInit := Succeeded(CoInitializeEx (nil, COINIT_APARTMENTTHREADED));

> FFoo2 := CoFoo2.Create;
> FFoo2.Connect;
> Connected := True;

> except
> on E: Exception do
> begin
> .....
> end;
> end;
> end;

> That works so far. After that the thread goes terminated.
> On Exit I want to destroy Foo2 in that way:

> destructor Main.Destroy;
> begin
> Foo1 := nil;
> inherited;
> end;

> destrucor Foo1.Destroy;
> begin
> Foo1.Disconnect;
> inherited;
> end;

> function Foo1.Disconnect;
> begin
> if Connected then
> begin

> if FFoo2.IsConnected then
> FFoo2.Disconnect;

> try
> FFoo2 := nil;
> // I get access violation here
> // I even cannot catch it with this try...except block.

> except
> on E: Exception do
> ShowMessage(E.Message);
> end;

> if ComInit then CoUninitialize;
> end;

> inherited;
> end;

Alex Penne

Delphi Developer

Tue, 11 Nov 2003 14:14:35 GMT

Re:Threads: Access violation on COM-Server destroing

Hello Binh,

The actual code is pretty large, I tried to extract the things where error
happens.

However I found a dirty workaround. If I calls Foo1.Connect with Synchronize
the release of Foo2 works very well. Have you an idea how can I get working
code without Synchronize-Function?

Alex

Quote

> Can you show your actual code that compiles? This code looks like its
> inconsitent and its hard to determine which is which.

> --
> have fun
> Binh Ly
> www.techvanguards.com

> "Alex Penner" <a...@c-studios.de> wrote in message
> news:3b0b7bd6$1_1@dnews...
> > procedure TThread.Execute;
> > begin
> > ...
> > Foo1.Connect;
> > ...
> > end;

> > function Foo1.Connect: boolean;
> > begin
> > if Connected then Exit;

> > try
> > ComInit := Succeeded(CoInitializeEx (nil,

COINIT_APARTMENTTHREADED));

- Show quoted text -

Quote

> > FFoo2 := CoFoo2.Create;
> > FFoo2.Connect;
> > Connected := True;

> > except
> > on E: Exception do
> > begin
> > .....
> > end;
> > end;
> > end;

> > That works so far. After that the thread goes terminated.
> > On Exit I want to destroy Foo2 in that way:

> > destructor Main.Destroy;
> > begin
> > Foo1 := nil;
> > inherited;
> > end;

> > destrucor Foo1.Destroy;
> > begin
> > Foo1.Disconnect;
> > inherited;
> > end;

> > function Foo1.Disconnect;
> > begin
> > if Connected then
> > begin

> > if FFoo2.IsConnected then
> > FFoo2.Disconnect;

> > try
> > FFoo2 := nil;
> > // I get access violation here
> > // I even cannot catch it with this try...except block.

> > except
> > on E: Exception do
> > ShowMessage(E.Message);
> > end;

> > if ComInit then CoUninitialize;
> > end;

> > inherited;
> > end;

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