fail to open contacts when use thread to visit contacts

[dznlong]

i create a new thread in my program based on S60.i debug my program by using VC IDE on S60 emulator. when the thread tried to open contact database,the thread was closed after failing to open contact database. i have used many ways to find the reason, i failed.who can tell me the reason?

my code in the follow:
void XXXXXXXX::CreateThread()
{
TInt error = iThreadHandlePackage.Create(_L( "HandlePackageByThread") ,
HandlePackageByThread,
1024*10, //stack size
1024*10, //min heap size
1024*60, //max heap size
iSyncInfo,
EOwnerThread);
if(error != KErrNone)
return;
iThreadHandlePackage.Resume();

iThreadCreated = ETrue;
iThreadRunning = ETrue;
}
TInt XXXXXXX::HandlePackageByThread(TAny *aPtr)
{
CContactDatabase* contactsDb;
TRAPD(error,contactsDb = CContactDatabase::OpenL();
if(error != KErrNone)
return FAIL_OPEN_DATABASE;
delete contactsDb;
}

[Mike24Productions]

Hi, i got the similar problem with anotha function FindWildByDir.
Actually, I had 3 issues:
- Define a cleanupstack
- TRAPD(myFunc)
- use & install an Activesheduler

I'm still having the problem, check "RThread FindWildByDir", I may get some cool answers
Mike

[aymenn]

hello,
Try initialising the CContactDatabase pointer, ie
CContactDatabase* contactsDb = 0;

Hope that helps,
Aymen

[dznlong]

hi,aymenn, thanks for your advise.
i tried by your method again.but it is not useful to resolve the program.

[hotcheese]

Try installing an active scheduler if you can't open the contacts database.

[aymenn]

In hindsight, I can see that if OpenL fails, the delete is never reached...

Still a good habit to get into i would say.

[dznlong]

i think it is symbian OS limitation. multi-threaded programs are uncommon in Symbian OS,some resources can only be used from the main thread.

[Paul.Todd]

As Hotcheese said, you need to have an active scheduler to use the contacts database.

More importantly you need to create a cleanup stack before you can use trap.

Look in the sample code or download the example for forum nokia for examples on using a thread and active objects

[dznlong]

thank for Paul's reply.i downloaded thread example project and add my code into thread function:
TInt CThreadEngine::ExecuteThreadTwo(TAny *aPtr)
{
// Convert pointer
CContactDatabase* contactsDb = NULL;


TRAPD(error,CleanupStack::PushL(contactsDb = CContactDatabase::OpenL(CContactDatabase::EMultiThread)));

if(error != KErrNone)
return error;
contactsDb->CloseTables();
CleanupStack::PopAndDestroy();

return KErrNone;


}

void CThreadEngine::ConstructL(CThreadAppView* aView)
{
CTimer::ConstructL();

iView = aView;
CActiveScheduler::Add( this );
}

i got the same result:fail to open contactdatabase!!!

[Paul.Todd]

Are you sure you you read the document?


You actually missed the most important point of my response which is that you need to create a cleanup stack before creating your active scheduler.

The following are missing:
Create a cleanup stack using a CTrapCleanup.
Create an active scheduler object for the thread.
Install an active scheduler on the thread for the thread.

Also I hope CThreadAppView is not derived from CView, you cannot use views across threads.

[dznlong]

Thank you,Paul. can you tell me how to Create an active scheduler object for the thread and Install an active scheduler on the thread for the thread?

[Paul.Todd]

I don't normally do peoples homework assignments for them but here is a simple example

TInt XXXXXXX::HandlePackageByThread(TAny *aPtr)
{
CTrapCleanup* cleanupStack = CTrapCleanup::New();
CActiveScheduler* activeScheduler = new CActiveScheduler;
CActiveScheduler::Install(activeScheduler);

// add your code here

// add some cleanup code do destroy the scheduler and cleanup objects
}

[dznlong]

I resolved my problem eventually by Paul's methods. Thank Paul very much.

[pavan]

I am also implementing the thread for contacts,same problem i am getting, i am not able to open contact data base.if any one know reply me, i am using the 3rd edition.


TInt xxxxxxxxx::GetContactListL(RContactDetailsArray** aContactNamesDPtr)
{

TInt lResult = KErrNone;
lResult = iContactsThread.Create( KContactThread,
xxxxx::GetContactsThreadFunction,
KDefaultStackSize,
KMinHeapSize,
KMinHeapSize+1000000,
this);
iContactsThread.SetPriority( EPriorityRealTime );
iContactsThread.Resume();

*aContactNamesDPtr = iContactDetailsArray;

return lResult;


}

TInt xxxxxxxxx::GetContactsThreadFunction(TAny *aData)
{
TInt lResult = KErrNone;
xxxr* lxx = static_cast<xxxxxxx*> (aData);

CTrapCleanup* lCleanupStack = CTrapCleanup::New();
TRAPD(lTrapErr,lContactDBManager->GetContactList());
if(lTrapErr != KErrNone)
{
lResult = lTrapErr;

}
delete lCleanupStack;

return lResult;
}


void xxxx::GetContactList()
{
TInt lResult = KErrNone;

if (NULL != iContactDbPtr)
{
delete iContactDbPtr;
iContactDbPtr = NULL;
}
CActiveScheduler* lActiveScheduler;
lActiveScheduler = new( ELeave )CActiveScheduler;
CActiveScheduler::Install( lActiveScheduler );
TRAP(lResult, iContactDbPtr = CContactDatabase::OpenL(CContactDatabase::EMultiThread));//here it's not opening

.........................
...................
}

[hotcheese]

You don't start the active scheduler