在 QString toUtf8(） 中崩溃

我有一个插槽：

void Foo::func(QString str1, const QString& str2, int width, int height)
{
    std::unique_lock<std::mutex> _lock(m_mutex);
#ifdef _DEBUG
    MEMORYSTATUSEX statex;
    statex.dwLength = sizeof (statex);
    if (GlobalMemoryStatusEx(&statex)) {
        qDebug() << QString("There are %1 free MB of physical memory.n").arg(statex.ullAvailPhys / 1024 / 1024);
    }
#endif
    BaseClass::someFunc(
        str1.toStdString(),
        str2.toUtf8().constData(),
        width,
        height
    );
}

这似乎是正确的，并且有效。但是，如果程序长时间工作（例如晚上），它会在此功能中崩溃

str2.toUtf8().constData()

我最初以为这是一个基于线程的错误，但我的锁不起作用。所有局部变量和类成员都可以。崩溃错误是：

First-chance exception at 0x76E45B68 foo.exe: Microsoft C++ exception: std::bad_alloc at memory location 0x00EFC6EC

但是从上面的代码中，最后一个 MEMORYSTATUSEX 显示可用内存是

There are 2314 free MB of physical memory

我也认为 str2 太大了，但它适用于 49152、168441等长度。问题出在哪里？我错过了什么吗？

堆栈跟踪：

    KernelBase.dll!_RaiseException@16()    Unknown
[External Code] 
Qt5Cored.dll!qBadAlloc() Line 2849  C++
Qt5Cored.dll!QByteArray::QByteArray(int size, Qt::Initialization __formal) Line 1409    C++
Qt5Cored.dll!QUtf8::convertFromUnicode(const QChar * uc, int len) Line 151  C++
Qt5Cored.dll!QString::toUtf8_helper(const QString & str) Line 4373  C++
Qt5Cored.dll!QString::toUtf8() Line 56  C++
foo.exe!Foo::func(QString str1, const QString & str2, int width, int height) Line 3600  C++
foo.exe!Foo::qt_static_metacall(QObject * _o, QMetaObject::Call _c, int _id, void * * _a) Line 1126 C++
Qt5Cored.dll!QMetaObject::activate(QObject * sender, int signalOffset, int local_signal_index, void * * argv) Line 3717 C++
Qt5Cored.dll!QMetaObject::activate(QObject * sender, const QMetaObject * m, int local_signal_index, void * * argv) Line 3582    C++
foo.exe!SomeClass::func(QString _t1, const QString & _t2, int _t3, int _t4) Line 137    C++
foo.exe!SomeClass::qt_static_metacall(QObject * _o, QMetaObject::Call _c, int _id, void * * _a) Line 81 C++
Qt5Cored.dll!QMetaCallEvent::placeMetaCall(QObject * object) Line 485   C++
Qt5Cored.dll!QObject::event(QEvent * e) Line 1246   C++
Qt5Widgetsd.dll!QApplicationPrivate::notify_helper(QObject * receiver, QEvent * e) Line 3720    C++
Qt5Widgetsd.dll!QApplication::notify(QObject * receiver, QEvent * e) Line 3164  C++
Qt5Cored.dll!QCoreApplication::notifyInternal(QObject * receiver, QEvent * event) Line 935  C++
Qt5Cored.dll!QCoreApplication::sendEvent(QObject * receiver, QEvent * event) Line 228   C++
Qt5Cored.dll!QCoreApplicationPrivate::sendPostedEvents(QObject * receiver, int event_type, QThreadData * data) Line 1552    C++
Qt5Cored.dll!QCoreApplication::sendPostedEvents(QObject * receiver, int event_type) Line 1410   C++
qwindowsd.dll!QWindowsGuiEventDispatcher::sendPostedEvents() Line 81    C++
Qt5Cored.dll!qt_internal_proc(HWND__ * hwnd, unsigned int message, unsigned int wp, long lp) Line 414   C++
[External Code] 
Qt5Cored.dll!QEventDispatcherWin32::processEvents(QFlags<enum QEventLoop::ProcessEventsFlag> flags) Line 807    C++
qwindowsd.dll!QWindowsGuiEventDispatcher::processEvents(QFlags<enum QEventLoop::ProcessEventsFlag> flags) Line 73   C++
Qt5Cored.dll!QEventLoop::processEvents(QFlags<enum QEventLoop::ProcessEventsFlag> flags) Line 129   C++
Qt5Cored.dll!QEventLoop::exec(QFlags<enum QEventLoop::ProcessEventsFlag> flags) Line 204    C++
Qt5Cored.dll!QCoreApplication::exec() Line 1188 C++
Qt5Guid.dll!QGuiApplication::exec() Line 1508   C++
Qt5Widgetsd.dll!QApplication::exec() Line 2957  C++
foo.exe!WinMain(HINSTANCE__ * __formal, HINSTANCE__ * __formal, char * lpCmdLine, int __formal) Line 348    C++
[External Code] 

提前感谢！