🚀 go-pugleaf

"Stefano Bonifazi" <stefboombastic@email.it> wrote in message
news:41ffbb99@newsgroups.borland.com...

> void __fastcall TForm2::ServerSocket1ClientConnect(TObject *Sender,
>       TCustomWinSocket *Socket)
> {
>  Memo1->Lines->Add("Client connected");
> }

You cannot do that.  In blocking mode, the server uses a separate worker
thread to listen for incoming connections.  The OnConnect event is triggered
in the context of that thread, not the main thread.  The VCL is not
thread-safe in general, and as such accessing the GUI directly from a worker
thread can be dangerous.  You must synchronize access to the GUI so that the
code accessing the GUI is executed in the context of the main thread only.

> void __fastcall TForm2::ServerSocket1ClientRead(TObject *Sender,
>       TCustomWinSocket *Socket)
> {
>  Memo1->Lines->Add("Inside OnClientRead");
>  Application->ProcessMessages();
>  Memo1->Lines->Add("Client: "+Socket->ReceiveText());
>  Application->ProcessMessages();
>  Socket->SendText("Bye!");
> }

Same here.  You are accessing the GUI in an unsafe manner, because
OnClientRead is going to be triggered in the context of a worker thread, not
the main thread.  Not only that, but you should never call ProcessMessages()
from the events of a blocking server, either.

> void __fastcall TForm2::ServerSocket1ClientWrite(TObject *Sender,
>       TCustomWinSocket *Socket)
> {
>  Memo1->Lines->Add("OnClientWrite");
>  Socket->SendText("Bye!");
> }

You don't need to use the OnClientWrite event with a blocking server.

> void __fastcall TForm2::ServerSocket1ClientError(TObject *Sender,
>       TCustomWinSocket *Socket, TErrorEvent ErrorEvent, int &ErrorCode)
> {
>  Memo1->Lines->Add("Error");
> }

Still accessing the GUI in an unsafe manner.

> It seems dead, nothing is written to the Memo :(

That is what happens when you do not access the GUI in a thread-safe manner.


Gambit