Delphi threading by example article in C++ Builder 2007 format

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4 total messages Started by na Wed, 28 May 2008 18:36

#285

Author: na
Date: Wed, 28 May 2008 18:36

9 lines
1213 bytes

In the Delphi threading by example article presented here:
http://dn.codegear.com/article/22411

I would like to implement a portion of this using C++ Builder. What is the correct syntax
for this funtion?

procedure HandleMessage(var Message: TMessage); message TH_MESSAGE;

I take it I need to use BEGIN_MESSAGE_MAP macros?

Re: Delphi threading by example article in C++ Builder 2007 format

#287

Author: Remy Lebeau (TeamB)
Date: Wed, 28 May 2008 20:11

30 lines
1789 bytes

"na" <na@na.com> wrote in message news:483da620$1@newsgroups.borland.com...

> In the Delphi threading by example article presented here:
> http://dn.codegear.com/article/22411
>
> I would like to implement a portion of this using C++ Builder.
> What is the correct syntax for this funtion?

Use a MESSAGE_MAP for that, ie:

    private:
        MESSAGE void __fastcall HandleMessage(TMessage &Message);

    public:
        BEGIN_MESSAGE_MAP
            VCL_MESSAGE_HANDLER(TH_MESSAGE, TMessage, HandleMessage)
        END_MESSAGE_MAP(TForm)


    void __fastcall TForm1::HandleMessage(TMessage &Message)
    {
        //....

        // this is not required for user-defined messages
        TForm::Dispatch(&Message);
    }


Gambit

Re: Delphi threading by example article in C++ Builder 2007 format

#286

Author: na
Date: Wed, 28 May 2008 20:35

28 lines
1742 bytes

Thank you Remy. Would you mind inspecting the following to see if it looks ok? It is very
brief to keep it simple. It works on my Quad core...

//File.h
class MSGObject
{
 private:
 public:
 std::string sLogMessage;
 std::string sWrkStation;
};

//File.cpp
void TForm1::OnMessage(TMessage & Message)
{
 if (Message.WParam == TH_COMPUTER)
  {
    MSGObject* pMSGObj = (MSGObject*)Message.LParam;
    lb_Computer->Caption = pMSGObj->sWrkStation.c_str();
    delete pMSGObj;
    pMSGObj = 0;
  }
}

//From a Thread
MSGObject * MSGObj = new MSGObject;
MSGObj->sWrkStation = "Some Value";
PostMessage(Form1->Handle, TH_MESSAGE, TH_COMPUTER, (long)MSGObj);

Re: Delphi threading by example article in C++ Builder 2007 format

#288

Author: Remy Lebeau (TeamB)
Date: Wed, 28 May 2008 23:04

27 lines
1901 bytes

"na" <na@na.com> wrote in message news:483dc218$1@newsgroups.borland.com...

> Would you mind inspecting the following to see if it looks ok?

You can do away with the wrapper class altogether, it is not needed:

    void TForm1::OnMessage(TMessage &Message)
    {
        if( Message.WParam == TH_COMPUTER )
        {
            AnsiString *pWrkStation = (AnsiString*) Message.LParam;
            lb_Computer->Caption = *pWrkStation;
            delete pWrkStation;
        }
    }

    AnsiString *pWrkStation = new AnsiString("Some Value");
    if( !PostMessage(Form1->Handle, TH_MESSAGE, TH_COMPUTER, (LPARAM) 
pWrkStation) )
        delete pWrkStation;

Either way, though, just make sure your TForm is actually processing all 
TH_MESSAGE messages, or you will leak your allocated objects/strings.


Gambit

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