problem with qsharedmemory

[daemonna]

i got following code and it looks like due to this code application crash (but still not sure, coz app is multithreaded)...

void simplex_user::user_to_mem()
{
    if(!usershm.isAttached())
        usershm.attach(QSharedMemory::ReadWrite);
    QByteArray usercache;
    QDataStream ucd(&usercache, QIODevice::ReadWrite);
    usercache.clear();
    usercache.resize(44+1);
    ucd.device()->seek(0);
 
    ucd << (quint8)this->status << (quint8)this->speed << (quint8)this->playernum   // 0 1 2
            << (quint8)this->lookat << (quint8)this->key1 << (quint8)this->key2     // 3 4 5
            << (quint8)this->gotpowerup1 << (quint8)this->gotpowerup2               // 6 7
            << (qint8)this->yoffset << (qint8)this->xoffset << (quint16)this->pos   // 8 9 10-11
            << (quint64)this->score << (quint64)this->adminkey << (quint64)this->playerid  // 12-19 20-27 28-35
            << (quint64)this->achievements << (quint8)this->flags;                         // 36-43 44
    usershm.lock();
    char *to = (char*)usershm.data();
    const char *from = this->data.data();
    memcpy(to, from, qMin(usershm.size(), usershm.size()));
    usershm.unlock();
 
 
}
 
void simplex_user::mem_to_user()
{
    bool ok;
    QByteArray usercache;
    usercache.resize(44+1);
 
    if(!usershm.isAttached())
        usershm.attach(QSharedMemory::ReadWrite);
    usershm.lock();
    usercache = QByteArray((char*)usershm.constData(), usershm.size()+1);
    this->data=usercache;
    usershm.unlock();
    this->status=usercache.mid(0,1).toHex().toUInt(&ok, 16);
    this->speed=usercache.mid(1,1).toHex().toUInt(&ok, 16);
    this->playernum=usercache.mid(2,1).toHex().toUInt(&ok, 16);
    this->lookat=usercache.mid(3,1).toHex().toUInt(&ok, 16);
    this->key1=usercache.mid(4,1).toHex().toUInt(&ok, 16);
    this->key2=usercache.mid(5,1).toHex().toUInt(&ok, 16);
    this->gotpowerup1=usercache.mid(6,1).toHex().toUInt(&ok, 16);
    this->gotpowerup2=usercache.mid(7,1).toHex().toUInt(&ok, 16);
    this->yoffset=usercache.mid(8,1).toHex().toUInt(&ok, 16);
    this->xoffset=usercache.mid(9,1).toHex().toUInt(&ok, 16);
    this->pos=usercache.mid(10,2).toHex().toUShort(&ok, 16);
    this->score=usercache.mid(12,8).toHex().toULongLong(&ok, 16);
    this->adminkey=usercache.mid(20,8).toHex().toULongLong(&ok, 16);
    this->playerid=usercache.mid(28,8).toHex().toULongLong(&ok, 16);
    this->achievements=usercache.mid(36,8).toHex().toULongLong(&ok, 16);
    this->flags=usercache.mid(44,8).toHex().toULongLong(&ok, 16);
}

void simplex_user::user_to_mem()
{
    if(!usershm.isAttached())
        usershm.attach(QSharedMemory::ReadWrite);
    QByteArray usercache;
    QDataStream ucd(&usercache, QIODevice::ReadWrite);
    usercache.clear();
    usercache.resize(44+1);
    ucd.device()->seek(0);

    ucd << (quint8)this->status << (quint8)this->speed << (quint8)this->playernum   // 0 1 2
            << (quint8)this->lookat << (quint8)this->key1 << (quint8)this->key2     // 3 4 5
            << (quint8)this->gotpowerup1 << (quint8)this->gotpowerup2               // 6 7
            << (qint8)this->yoffset << (qint8)this->xoffset << (quint16)this->pos   // 8 9 10-11
            << (quint64)this->score << (quint64)this->adminkey << (quint64)this->playerid  // 12-19 20-27 28-35
            << (quint64)this->achievements << (quint8)this->flags;                         // 36-43 44
    usershm.lock();
    char *to = (char*)usershm.data();
    const char *from = this->data.data();
    memcpy(to, from, qMin(usershm.size(), usershm.size()));
    usershm.unlock();


}

void simplex_user::mem_to_user()
{
    bool ok;
    QByteArray usercache;
    usercache.resize(44+1);

    if(!usershm.isAttached())
        usershm.attach(QSharedMemory::ReadWrite);
    usershm.lock();
    usercache = QByteArray((char*)usershm.constData(), usershm.size()+1);
    this->data=usercache;
    usershm.unlock();
    this->status=usercache.mid(0,1).toHex().toUInt(&ok, 16);
    this->speed=usercache.mid(1,1).toHex().toUInt(&ok, 16);
    this->playernum=usercache.mid(2,1).toHex().toUInt(&ok, 16);
    this->lookat=usercache.mid(3,1).toHex().toUInt(&ok, 16);
    this->key1=usercache.mid(4,1).toHex().toUInt(&ok, 16);
    this->key2=usercache.mid(5,1).toHex().toUInt(&ok, 16);
    this->gotpowerup1=usercache.mid(6,1).toHex().toUInt(&ok, 16);
    this->gotpowerup2=usercache.mid(7,1).toHex().toUInt(&ok, 16);
    this->yoffset=usercache.mid(8,1).toHex().toUInt(&ok, 16);
    this->xoffset=usercache.mid(9,1).toHex().toUInt(&ok, 16);
    this->pos=usercache.mid(10,2).toHex().toUShort(&ok, 16);
    this->score=usercache.mid(12,8).toHex().toULongLong(&ok, 16);
    this->adminkey=usercache.mid(20,8).toHex().toULongLong(&ok, 16);
    this->playerid=usercache.mid(28,8).toHex().toULongLong(&ok, 16);
    this->achievements=usercache.mid(36,8).toHex().toULongLong(&ok, 16);
    this->flags=usercache.mid(44,8).toHex().toULongLong(&ok, 16);
}

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is anything wrong with this code?

[daemonna]

usershm.lock();
    char *to = (char*)usershm.data();
    const char *from = this->data.data();
    memcpy(to, from, qMin(usershm.size(), usershm.size()));
    usershm.unlock();

usershm.lock();
    char *to = (char*)usershm.data();
    const char *from = this->data.data();
    memcpy(to, from, qMin(usershm.size(), usershm.size()));
    usershm.unlock();

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fixed... usercache replaced this->data.data();... but app still crash...