QLocalServer crashes when QString is used instead of "string_literal"

ashishbansal

Hi everyone,

Qt application is crashing for me when I use "string_literal" instead of QString in QLocalServer::listen .

Here's my code :

SingleInstance::SingleInstance(int argc, char *argv[]) :
    QApplication(argc, argv),
    mServerName("foo")
{
    mLocalSocket = new QLocalSocket();
    mLocalSocket->connectToServer(mServerName);
    if (mLocalSocket->waitForConnected(mTimeToWait)) {
        askForMainWindow();
        ::exit(0);
    }

    mLocalServer = new QLocalServer();
    mLocalServer->setSocketOptions(QLocalServer::UserAccessOption);
    connect(mLocalServer, &QLocalServer::newConnection, this, &SingleInstance::clientConnected);
    mLocalServer->listen(mServerName);
}

This is crashing for me. And if replace mServerName with "foo".
Does anyone know the reason for this ?
(BTW this class is inheriting QApplication and event loop hasn't been started yet.)

Here 's backtrace :


(gdb) bt
#0  0x00007ffff60210ca in strlen () from /usr/lib/libc.so.6
#1  0x00007ffff6e63c41 in QCoreApplication::arguments() () from /usr/lib/libQt5Core.so.5
#2  0x00007fffed464fb2 in ?? () from /usr/lib/libQt5XcbQpa.so.5
#3  0x00007fffed465bb4 in ?? () from /usr/lib/libQt5XcbQpa.so.5
#4  0x00007fffecfe9c38 in _SmcProcessMessage () from /usr/lib/libSM.so.6
#5  0x00007fffecdd946c in IceProcessMessages () from /usr/lib/libICE.so.6
#6  0x00007ffff6e8f31a in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/libQt5Core.so.5
#7  0x00007ffff6f0f21e in QSocketNotifier::activated(int, QSocketNotifier::QPrivateSignal) () from /usr/lib/libQt5Core.so.5
#8  0x00007ffff6e9be3b in QSocketNotifier::event(QEvent*) () from /usr/lib/libQt5Core.so.5
#9  0x00007ffff78a79ac in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQt5Widgets.so.5
#10 0x00007ffff78ace86 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQt5Widgets.so.5
#11 0x00007ffff6e60bab in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQt5Core.so.5
#12 0x00007ffff6eb7a1d in ?? () from /usr/lib/libQt5Core.so.5
#13 0x00007ffff586cdc7 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#14 0x00007ffff586d020 in ?? () from /usr/lib/libglib-2.0.so.0
#15 0x00007ffff586d0cc in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#16 0x00007ffff6eb754f in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#17 0x00007ffff6e5e57a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#18 0x00007ffff6e6653c in QCoreApplication::exec() () from /usr/lib/libQt5Core.so.5
#19 0x00000000004351c0 in main (argc=1, argv=0x7fffffffe4a8) at /home/phantom/devel/sdm/main.cpp:31

Is this a bug in Qt ?

Moreover, I'm using Qt5.5.1 and gcc version 5.3.0 (GCC)

SGaist

Hi,

Not a direct answer but are you trying to reimplement QtSingleApplication ?

ashishbansal

@SGaist said:

Hi,

Not a direct answer but are you trying to reimplement QtSingleApplication ?

Yeah

SGaist

Why not use it ? IIRC It's been ported to Qt 5

ashishbansal

@SGaist said:

Why not use it ? IIRC It's been ported to Qt 5

Oh, I didn't know that.

SGaist

It's in the QtSolution module and there's a fix for Qt 5.5 so yes, it's been ported :)

ashishbansal

@SGaist said:

It's in the QtSolution module and there's a fix for Qt 5.5 so yes, it's been ported :)

Okay, Thanks a lot :)