examples/Base/ThreadsAndProcesses/TLS1/TLS1dll.cpp

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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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