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<task xml:lang="en" id="GUID-E2D4973C-FE93-5DE7-B04E-19B7701621C3"><title>Call Swap Tutorial </title><shortdesc>This tutorial describes how to swap calls with the telephony API for applications. </shortdesc><prolog><metadata><keywords/></metadata></prolog><taskbody> <steps id="GUID-B8135064-5C8F-5EE1-9F58-9A8A9CCED402"> <step id="GUID-87A34CB4-69CB-59EB-BE40-E4CFD64334BB"><cmd/><info>create a new instance of <xref href="GUID-97D402C8-B4B7-385A-92B3-D3FCC0CA575A.dita"><apiname>CTelephony</apiname></xref>  </info> </step> <step id="GUID-A3EB36C9-9856-5AA4-8E64-6BE8282CEAB1"><cmd/><info>use <xref href="GUID-97D402C8-B4B7-385A-92B3-D3FCC0CA575A.dita"><apiname>CTelephony::GetCallDynamicCaps()</apiname></xref> to check if the device supports swap function </info> </step> <step id="GUID-135949F6-5864-5BD4-A8B1-253CE994AB44"><cmd/><info>call <xref href="GUID-97D402C8-B4B7-385A-92B3-D3FCC0CA575A.dita"><apiname>CTelephony::Swap()</apiname></xref> when you have an active call and a call on hold </info> <info>The function makes the held call active and the puts the active call on hold. Pass the function the IDs of the two calls. The IDs are <xref href="GUID-97D402C8-B4B7-385A-92B3-D3FCC0CA575A.dita"><apiname>CTelephony::TCallId</apiname></xref> objects returned when you dialled or answered the calls. </info> </step> <step id="GUID-2B849097-C643-59E7-95FA-708061ED71E3"><cmd/><info>pass the enumeration <xref href="GUID-97D402C8-B4B7-385A-92B3-D3FCC0CA575A.dita"><apiname>CTelephony::ESwapCancel</apiname></xref> to cancel the asynchronous request </info> </step> </steps> <example id="GUID-24851381-E70A-53F5-AFDB-41B5D8DEB172"><title>Call swap example</title> <codeblock id="GUID-D28043B3-811B-5A73-B42B-E79A5BCCC481" xml:space="preserve">#include &lt;e32base.h&gt;

#include <Etel3rdParty.h>

class CClientApp : public CActive

    { 

private:

    CTelephony* iTelephony;

    CTelephony::TCallId iCallIdA;

    CTelephony::TCallId iCallIdB;

public:

    CClientApp(CTelephony* aTelephony, CTelephony::TCallId aCallIdA, CTelephony::TCallId aCallIdB);

    TInt SomeFunction();

private:

    /*

       These are the pure virtual methods from CActive that  

       MUST be implemented by all active objects

       */

    void RunL();

    void DoCancel();

   };

CClientApp::CClientApp(CTelephony* aTelephony, CTelephony::TCallId aCallId)

    : CActive(EPriorityStandard),

      iTelephony(aTelephony),

      iCallIdA(aCallIdA)

      iCallIdB(aCallIdB)

    {

    //default constructor

    }

TInt CClientApp::SomeFunction()

    {

    // Check that the phone supports Resuming calls.

    CTelephony::TCallCapsV1 callCapsV1;

    CTelephony::TCallCapsV1Pckg callCapsV1Pckg(callCapsV1);

    iTelephony->GetCallDynamicCaps(iCallId, callCapsV1Pckg);

    if( callCapsV1.iControlCaps & CTelephony::KCapsSwap )

       {

       // The call represented by 'iCallId' can be swapped

       iTelephony->Swap(iStatus, iCallIdA, iCallIdB);

       SetActive();

       return KErrNone;

       }

    else

       {

       // The call cannot be swapped; 

       // return an error indicate this.

       return KErrNotSupported;

       }

    }

void CClientApp::RunL()

    {

    if(iStatus==KErrNone)

       {} // The call has been swapped successfully;

    }

void CClientApp::DoCancel()

    {

    iTelephony->CancelAsync(CTelephony::ESwapCancel);

    }