shared memory wont attach

[daemonna]

here is my code:

QSharedMemory numofallplayers;
 
void sesman::run()
{
    numofallplayers.setKey("numofallplayers");
    numofallplayers.create(sizeof(qint64), QSharedMemory::ReadWrite);
 
    qDebug() << "session manager thread starts from" << QThread::currentThread();
    qDebug() << "seting total players to zero";
    sesman::SetNumOfAllPlayers(0);
    qDebug() << "num of players total: " << sesman::GetNumOfAllPlayers();  //just to check
.
.
.
    cleanup();
}
 
 
void sesman::SetNumOfAllPlayers(qint64 totalplayers)
{
    if(numofallplayers.isAttached()){
        numofallplayers.detach();
    }
    if(!numofallplayers.attach(QSharedMemory::ReadWrite)){
        //some error
        qDebug() << "attach numofallplayers failed" << numofallplayers.errorString();
    }
    numofallplayers.lock();
    qint64* totalpl = (qint64*)numofallplayers.data();
    *totalpl = totalplayers;
    numofallplayers.unlock();
    if(!numofallplayers.detach())
        qDebug() << "unable to detach";
}

QSharedMemory numofallplayers;

void sesman::run()
{
    numofallplayers.setKey("numofallplayers");
    numofallplayers.create(sizeof(qint64), QSharedMemory::ReadWrite);

    qDebug() << "session manager thread starts from" << QThread::currentThread();
    qDebug() << "seting total players to zero";
    sesman::SetNumOfAllPlayers(0);
    qDebug() << "num of players total: " << sesman::GetNumOfAllPlayers();  //just to check
.
.
.
    cleanup();
}


void sesman::SetNumOfAllPlayers(qint64 totalplayers)
{
    if(numofallplayers.isAttached()){
        numofallplayers.detach();
    }
    if(!numofallplayers.attach(QSharedMemory::ReadWrite)){
        //some error
        qDebug() << "attach numofallplayers failed" << numofallplayers.errorString();
    }
    numofallplayers.lock();
    qint64* totalpl = (qint64*)numofallplayers.data();
    *totalpl = totalplayers;
    numofallplayers.unlock();
    if(!numofallplayers.detach())
        qDebug() << "unable to detach";
}

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and i get following error

seting total players to zero
attach numofallplayers failed "QSharedMemory::handle:: UNIX key file doesn't exist"
The program has unexpectedly finished.

Can someone help? what is wrong with my code?

thanks a lot for any help...

[tbscope]

Can you check if the following line succeeded?

numofallplayers.create(sizeof(qint64), QSharedMemory::ReadWrite);

numofallplayers.create(sizeof(qint64), QSharedMemory::ReadWrite);

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[daemonna]

problem wasn't in shared memory, but in a threading I'm using... so now I know I have to call sharedmemory.create in beginning of every thread, so i make sure it's created before any thread attach it... and in threading you never know which thread will be first