QSqlDatabase::close() sigsev exception

Hello,

posting code here is quite endless because is a big lot of code...I don't want to waste your precious time :)
Instead I ask for tips about a strange behavior:
I have a nice QSqlDatabase object, valid, open and cute, everything works fine. Once in a day it has to be closed, so I do
Code:

// QVector<QSqlDatabase> *vHandle; // vector of connections // int vIndex; // current index=0, vHandle->count()=1 QSqlDatabase app=vHandle->at(vIndex); app.close(); // ! exception vHandle->replace(vIndex,app);
app.close() raises exception, in detail QMYSQLDriver::close() does, and more in detail mysql_close(d->mysql) does (I can't go deeper debugging).
So the question is: why should QSqlDatabase::close() raise exception? Aware of this I could find my issue easier.

EDIT: it is not just close()! Also mysql_real_query raises exception when executing query (QSqlQuery::exec())... now I have to understand why it has to crash instead of warn/fail/anything-else-nicer... any idea?

Thanks thanks thanks.