I am using Qt 5.5 on Windows 8.1. When I run the code below, the application is able to get through one iteration, but crashes on the second one. 100% reproducible. (Copy/paste it into a Qt Creator instance and test; it might work for you).
#include <QCoreApplication> #include <QDebug> #include <utility> using std::pair; int main(int argc, char *argv[]) { QCoreApplication a(argc, argv); QMap<QString, pair<QString, QString> > table_def = { {"alpha", {"INTEGER", "PRIMARY KEY"}}, {"beta", {"VARCHAR", ""}}, {"gamma", {"VARCHAR", ""}}, {"delta", {"REAL", "DEFAULT 0"}}, {"epsilon", {"INTEGER", ""}}, {"zeta", {"INTEGER", ""}}, {"eta", {"INTEGER", ""}}, {"theta", {"INTEGER", ""}}, {"iota", {"VARCHAR", ""}}, {"kappa", {"INTEGER", "DEFAULT 0"}}, {"lambda", {"INTEGER", "DEFAULT 0"}} }; QMapIterator<QString, pair<QString, QString> > it(table_def); while (it.hasNext()) { it.next(); const QString& col_name = it.key(); qDebug() << col_name; const QString& col_type = it.value().first; qDebug() << col_type; const QString& extra_def = it.value().second; qDebug() << extra_def; } return a.exec(); } My Visual Studio debugger says: Unhandled exception at 0x000000006904E394 (Qt5Cored.dll) in helloqt.exe: 0xC0000005: Access violation reading location 0xFFFFFFFFFFFFFFFF.
If it is of any relevance, I added DEFINES += Q_COMPILER_INITIALIZER_LISTS in my project file to enable initialization of QContainers with initializer lists. Also, if I replace the STL pair with QPair, the application crashes at the first iteration.
I don't see anything wrong with this code. What could be happening?