examples/Base/ThreadsAndProcesses/TLS1/TLS1dll.cpp

// Copyright (c) 2000-2009 Nokia Corporation and/or its subsidiary(-ies).
// All rights reserved.
// This component and the accompanying materials are made available
// under the terms of "Eclipse Public License v1.0"
// which accompanies this distribution, and is available
// at the URL "http://www.eclipse.org/legal/epl-v10.html".
//
// Initial Contributors:
// Nokia Corporation - initial contribution.
//
// Contributors:
//
// Description:
// DLL example program (1) to demonstrate Thread Local Storage (TLS).
// This DLL implements the two classes CSetter and CGeneral
// CSetter is used to set up the static text string, delete it, change it and display
// its content.
// CGeneral can show the content.
// The point being made here is that the text string is, effectively, static writeable data.
// It is accessible by all classes implemented in the DLL.
// CSetter is the only class which sets the static data in this example but, in general,
// any class implemented in the DLL can change/delete/fetch the data
// through the pointer in thread local storage - it is a matter of application design.
//

#include "TLS1dll.h"

#include <e32uid.h>

_LIT(KTxt1,"<>\n");
_LIT(KFormat1,"<%S>\n");

//
// Class CSetter implementation
//

        // C++ constructor sets reference to the console in the
        // initializer list.
    // Body of constructor is empty.
    // Constructor is exported because it is non-trivial
EXPORT_C CSetter::CSetter(CConsoleBase& aConsole)
        : iConsole(aConsole)
        {
        }


        // Destructor, deletes the static string
CSetter::~CSetter()
        {
        delete (HBufC*)Dll::Tls();
        Dll::SetTls(NULL);
        }


        // Delete any existing static string; allocates a new HBufC
        // and sets thread local storage to point to the HBufC.
EXPORT_C void CSetter::SetStaticTextL(const TDesC& aString)
        {
        delete (HBufC*)Dll::Tls();
        HBufC* pD = aString.AllocL();
        Dll::SetTls(pD);
        }


        // Show static text
EXPORT_C void  CSetter::ShowStaticText() const
        {
        TDesC* text = ((TDesC*)Dll::Tls());
        
        if (text)
                iConsole.Printf(KFormat1, text);
        else
                iConsole.Printf(KTxt1);
        }



//
// Class CGeneral implementation
//

        // C++ constructor sets refrence to the console in the
        // initializer list.
    // Body of constructor is empty.
    // Constructor is exported because it is non-trivial
EXPORT_C CGeneral::CGeneral(CConsoleBase& aConsole)
        : iConsole(aConsole)
        {
        }


        // Show static text
EXPORT_C void  CGeneral::ShowStaticText() const
        {
        TDesC* text = ((TDesC*)Dll::Tls());
        
        if (text)
                iConsole.Printf(KFormat1, text);
        else
                iConsole.Printf(KTxt1);
        }

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