Qt分割故障

Question

I must develop a social network simulator using C++ and QT library. I store user into mysql database using QODBC. When i run my application, i throw a SIGSEGV error.

here, my function which throw this error :

QMutex userMutex;
userMutex.lock();

QListIterator<User*> i(users);
User* user;
QString sql = "insert into t_user (id, pseudo, name, firstname, birthdate) values ";
QString bindValue = QString::fromStdString("(?, ?, ?, ?, ?),").repeated(users.count());
sql.append(bindValue);
QSqlQuery query = QSqlQuery(Interface::getCnx());
query.prepare(sql);
while(i.hasNext())
{
    user = i.next();
    query.addBindValue(QString::number(user->getId()));
    query.addBindValue(user->getPseudo());
    query.addBindValue(user->getName());
    query.addBindValue(user->getFirstname());
    QString birthdate = QString::number(user->getBirthDate().year()) + "-" + QString::number(user->getBirthDate().month()) + "-" + QString::number(user->getBirthDate().day());
    query.addBindValue(birthdate);
}
query.exec();

userMutex.unlock();

It is "query.exec()" line which throw this error.

Do you see what's wrong?

Answer 1

First of all you have an extra comma here:

QString bindValue = QString::fromStdString("(?, ?, ?, ?, ?),").repeated(users.count());

So or you "repeat" string count-1 times and then add "(?, ?, ?, ?, ?)":

QString bindValue = QString::fromStdString("(?, ?, ?, ?, ?),").repeated(users.count() - 1);
bindValue "(?, ?, ?, ?, ?)";

Or you have to remove last char of your string bindValue.

Answer 2

I found the answer ... i guess. This SIGSEGV error has disappeared when i decrease the size of the list. Before the list contains 1000 users but now it constains only 800 users per call to this méthod.

Thanks for your help.