[Qt 5.2 msvc x64] QMYSQL invalid driver handle

konserw

Hello all, as this is my first post :)
Ad meritum:
QMYSQL driver return incorrect driver handle (i think), as following snippet throws "read access voilation" exception with mysql_ping function:
@
QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL", "initialConnection");
if(!db.isValid())
{
qCritical() << "Initial connection invalid!";
return QStringList();
}
db.setHostName("192.168.1.2");
db.setPort(3306);
db.setUserName("kOf_GetUsers");
db.setPassword("");
db.setDatabaseName("kOferta");
db.setConnectOptions("CLIENT_SSL=1;CLIENT_IGNORE_SPACE=1;MYSQL_OPT_RECONNECT=1");

qDebug() << "connName:" << db.connectionName();
qDebug() << "driver:" << db.driverName();
qDebug() << "options:" << db.connectOptions();
qDebug() << "host:" << db.hostName();
qDebug() << "database error:" << db.lastError().databaseText();
qDebug() << "driver error:" << db.lastError().driverText();

QSqlDriver* driver = db.driver();
qDebug() << "driver info";
driver->dumpObjectInfo();
driver->dumpObjectTree();

QVariant v = driver->handle();
if (v.isValid() && qstrcmp(v.typeName(), "MYSQL*")==0)
{
qDebug() << "v.typename:" << v.typeName();

MYSQL *handle = static_cast<MYSQL *>(v.data());
if (handle != NULL)
{
    qDebug() << "handle:" << handle;
    qDebug() << "mysql error:" << mysql_error(handle);

    try
    {
        qDebug() << "mysql ping:" << mysql_ping(handle);
        qDebug() << "mysql error:" << mysql_error(handle);

//                mysql_ssl_set(handle, ":/client-key", ":/client-cert", ":/ca-cacert", NULL, NULL);
 //       mysql_ssl_set(handle, "D:/git/build-kOferta/client-key.pem", "D:/git/build-kOferta/client-cert.pem", "D:/git/build-kOferta/ca-cacert.pem", "D:/git/build-kOferta/", "DHE-RSA-AES256-SHA");
    }
    catch (std::exception& e)
    {
        qCritical() << "[mysql_ssl_set] Standard exception: " << e.what();
    }
    catch(...)
    {
        qCritical() << "[mysql_ssl_set] Unknown exception";
    }
}

}
@
And my log is as follows:
@
[28.12.2013 11:09:47]: connName: "initialConnection"
[28.12.2013 11:09:47]: driver: "QMYSQL"
[28.12.2013 11:09:47]: options: "CLIENT_SSL=1;CLIENT_IGNORE_SPACE=1;MYSQL_OPT_RECONNECT=1"
[28.12.2013 11:09:47]: host: "192.168.1.2"
[28.12.2013 11:09:47]: database error: ""
[28.12.2013 11:09:47]: driver error: ""
[28.12.2013 11:09:47]: driver info
[28.12.2013 11:09:47]: OBJECT QMYSQLDriver::unnamed
[28.12.2013 11:09:47]: SIGNALS OUT
[28.12.2013 11:09:47]: <None>
[28.12.2013 11:09:47]: SIGNALS IN
[28.12.2013 11:09:47]: <None>
[28.12.2013 11:09:47]: QMYSQLDriver::
[28.12.2013 11:09:47]: v.typename: MYSQL*
[28.12.2013 11:09:47]: handle: 0x2c99f0
[28.12.2013 11:09:47]: mysql error:
@

What else can i check? What may be the cause? I use libmysql from MySQL Connector C 6.1 6.1.2 - i dont know if it is relevant...

Best regards, konserw

mapron

@ MYSQL *handle = *static_cast<MYSQL **>(v.data());@
and
@MYSQL *handle = static_cast<MYSQL *>(v.data());@
seems to be different lines according to docs (different pointer addresses).
Could you try another variant?

mapron

if we have CustomType inside Qvariant, type() will be CustomType and .data() return pointer to CustomType.
If your type is pointer to MYSQL... maybe that is the point?

konserw

Thank you very much. Casting to MYSQL** helped.
I wonder when this was changed, becouse cast to MYSQL* worked in qt 4.8...

konserw

Ok, not realy helped, because dereferenced MYSQL** is NULL, so either thios cast is wrong, or something with my database connection code :/
Could anyone help me with that? Mabey some working example, how this should be done?

konserw

ok, it's bug in QMYSQL:
https://bugreports.qt-project.org/browse/QTBUG-3500#comment-226912

dawidos

I've used this patch/diff from post above on QT 5.2. Then I've recompiled QT and seems working, but I have to made some tests to make sure that everything is fine. konserw if you want you can email to me

KR Dawid