QAudioDeviceInfo在 Windows上似乎存在内存泄漏（Qt 5.15.18）

编程语言 2026-07-11

Body

我在Windows上使用QAudioDeviceInfo::availableDevices()（Qt版本5.15.18）时，遇到了持续的内存泄漏问题——尚未在其他平台上测试。

Background

需要实现一个实时检测，用以判断某个音频设备是否出现在Windows上。为此，我会定期使用QAudioDeviceInfo::availableDevices() 来列出音频输入设备。然而，我发现进程的内存使用量会无限增长，表明出现了内存泄漏。

最小可复现示例：

#include <QApplication>
#include <QAudioDeviceInfo>
#include <QDebug>
#include <QPushButton>
#include <QTimer>
#include <QVBoxLayout>

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    QWidget *w = new QWidget();
    w->resize(400, 300);
    w->show();

    QTimer *timer = new QTimer(w);
    QObject::connect(timer, &QTimer::timeout, w, [w]() {
        qDebug() << "Timer timeout";
        // Get list of available audio input devices
        QList<QAudioDeviceInfo> devices = QAudioDeviceInfo::availableDevices(QAudio::AudioInput);
        // Iterate through devices and print names
        for (const QAudioDeviceInfo &device : devices)
        {
            qDebug() << "Device Name:" << device.deviceName();
        }
    });
    // Trigger device check every 100ms
    timer->start(100);

    int ret = app.exec();

    delete w;

    return ret;
}

观察到的行为：

在Windows上运行这段代码时：

进程的内存使用量（在任务管理器/资源监视器中可见）会随时间持续增加
尽管 QList<QAudioDeviceInfo> 设备是一个栈分配的变量（应该在lambda回调退出时被销毁），但内存并未释放

使用Visual Leak Detector (VLD) 进行验证

我已经通过Visual Leak Detector (VLD)，这是一个在Windows/MSVC上广泛使用的内存泄漏检测工具，确认了内存泄漏。

VLD在多次调用QAudioDeviceInfo::availableDevices() 时会报告内存泄漏
如果我移除对availableDevices() 的调用，则不会报告泄漏
这证实泄漏源自Qt的 QAudioDeviceInfo实现内部

我已检查的内容：

我期望每次定时器回调后，栈分配的设备列表及其QAudioDeviceInfo元素能够被正确释放
关于Qt 5.15.18的此内存泄漏，尚未发现相关的bug报告
该问题在多台Windows机器上可稳定重现

问题：

这是Qt 5.15.18的 QAudioDeviceInfo::availableDevices() 在Windows上的已知问题吗？
我是不是在代码中遗漏了什么，导致内存泄漏（例如错误的内存管理）？
有没有可行的变通方案，可以在不产生内存泄漏的前提下安全地获取音频设备信息？

VLD报告：

---------- Block 182 at 0x0000000039725760: 78 bytes ----------
  Leak Hash: 0x68333E06, Count: 1, Total 78 bytes
  Call Stack (TID 31932):
    ntdll.dll!RtlAllocateHeap()
    MMDevAPI.DLL!0x00007FF99F45ED72()
    MMDevAPI.DLL!0x00007FF99F452FE2()
    wdmaud.drv!0x00007FF9327F4E6C()
    wdmaud.drv!0x00007FF9327F3298()
    wdmaud.drv!0x00007FF9327F7610()
    winmmbase.dll!0x00007FF952AE65DD()
    winmmbase.dll!0x00007FF952AEFB7F()
    qtaudio_windowsd.dll!0x00007FF8F5C840E8()
    qtaudio_windowsd.dll!0x00007FF8F5C83E68()
    qtaudio_windowsd.dll!0x00007FF8F5C83BDD()
    D:\B\Q\qtmultimedia\src\multimedia\audio\qaudiodevicefactory.cpp (204): Qt5Multimediad.dll!QAudioDeviceFactory::audioDeviceInfo() + 0x27 bytes
    D:\B\Q\qtmultimedia\src\multimedia\audio\qaudiodeviceinfo.cpp (68): Qt5Multimediad.dll!QAudioDeviceInfoPrivate::QAudioDeviceInfoPrivate() + 0x23 bytes
    D:\B\Q\qtmultimedia\src\multimedia\audio\qaudiodeviceinfo.cpp (443): Qt5Multimediad.dll!QAudioDeviceInfo::QAudioDeviceInfo() + 0x3A bytes
    D:\B\Q\qtmultimedia\src\multimedia\audio\qaudiodevicefactory.cpp (135): Qt5Multimediad.dll!QAudioDeviceFactory::availableDevices() + 0x22 bytes
    D:\B\Q\qtmultimedia\src\multimedia\audio\qaudiodeviceinfo.cpp (435): Qt5Multimediad.dll!QAudioDeviceInfo::availableDevices() + 0xE bytes
    D:\Home\Desktop\mm\src\main.cpp (23): app.exe!<lambda_972f05a238b8c048bbd3e638a6c9cd17>::operator()() + 0xD bytes
    D:\Qt\Qt5.15.18-msvc2022_64\include\QtCore\qobjectdefs_impl.h (146): app.exe!QtPrivate::FunctorCall<QtPrivate::IndexesList<>,QtPrivate::List<>,void,<lambda_972f05a238b8c048bbd3e638a6c9cd17> >::call() + 0xA bytes
    D:\Qt\Qt5.15.18-msvc2022_64\include\QtCore\qobjectdefs_impl.h (256): app.exe!QtPrivate::Functor<<lambda_972f05a238b8c048bbd3e638a6c9cd17>,0>::call<QtPrivate::List<>,void>() + 0xF bytes
    D:\Qt\Qt5.15.18-msvc2022_64\include\QtCore\qobjectdefs_impl.h (443): app.exe!QtPrivate::QFunctorSlotObject<<lambda_972f05a238b8c048bbd3e638a6c9cd17>,0,QtPrivate::List<>,void>::impl() + 0x1B bytes
    D:\B\Q\qtbase\src\corelib\kernel\qobjectdefs_impl.h (398): Qt5Cored.dll!QtPrivate::QSlotObjectBase::call() + 0x42 bytes
    D:\B\Q\qtbase\src\corelib\kernel\qobject.cpp (3928): Qt5Cored.dll!doActivate<0>() + 0x2F bytes
    D:\B\Q\qtbase\src\corelib\kernel\qobject.cpp (3988): Qt5Cored.dll!QMetaObject::activate() + 0x13 bytes
    D:\B\Q\build-msvc\qtbase\src\corelib\.moc\debug\moc_qtimer.cpp (205): Qt5Cored.dll!QTimer::timeout() + 0x19 bytes
    D:\B\Q\qtbase\src\corelib\kernel\qtimer.cpp (259): Qt5Cored.dll!QTimer::timerEvent() + 0xF bytes
    D:\B\Q\qtbase\src\corelib\kernel\qobject.cpp (1324): Qt5Cored.dll!QObject::event() + 0x2E bytes
    D:\B\Q\qtbase\src\widgets\kernel\qapplication.cpp (3640): Qt5Widgetsd.dll!QApplicationPrivate::notify_helper() + 0x1F bytes
    D:\B\Q\qtbase\src\widgets\kernel\qapplication.cpp (2980): Qt5Widgetsd.dll!QApplication::notify() + 0x1D bytes
    D:\B\Q\qtbase\src\corelib\kernel\qcoreapplication.cpp (1064): Qt5Cored.dll!QCoreApplication::notifyInternal2() + 0x2E bytes
    D:\B\Q\qtbase\src\corelib\kernel\qcoreapplication.cpp (1463): Qt5Cored.dll!QCoreApplication::sendEvent()
    D:\B\Q\qtbase\src\corelib\kernel\qeventdispatcher_win.cpp (432): Qt5Cored.dll!QEventDispatcherWin32Private::sendTimerEvent() + 0x13 bytes
    D:\B\Q\qtbase\src\corelib\kernel\qeventdispatcher_win.cpp (256): Qt5Cored.dll!qt_internal_proc() + 0x11 bytes
    USER32.dll!CallWindowProcW() + 0x6A6 bytes
    USER32.dll!IsWindowUnicode() + 0x3CD bytes
    D:\B\Q\qtbase\src\corelib\kernel\qeventdispatcher_win.cpp (597): Qt5Cored.dll!QEventDispatcherWin32::processEvents() + 0xB bytes
    qwindowsd.dll!0x00007FF89FB00024()
    D:\B\Q\qtbase\src\corelib\kernel\qeventloop.cpp (143): Qt5Cored.dll!QEventLoop::processEvents()
    D:\B\Q\qtbase\src\corelib\kernel\qeventloop.cpp (235): Qt5Cored.dll!QEventLoop::exec() + 0x41 bytes
    D:\B\Q\qtbase\src\corelib\kernel\qcoreapplication.cpp (1375): Qt5Cored.dll!QCoreApplication::exec() + 0x22 bytes
    D:\B\Q\qtbase\src\gui\kernel\qguiapplication.cpp (1871): Qt5Guid.dll!QGuiApplication::exec()
    D:\B\Q\qtbase\src\widgets\kernel\qapplication.cpp (2833): Qt5Widgetsd.dll!QApplication::exec()
    D:\Home\Desktop\mm\src\main.cpp (31): app.exe!main() + 0x6 bytes
    D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl (79): app.exe!invoke_main()
    D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl (288): app.exe!__scrt_common_main_seh() + 0x5 bytes
    D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl (331): app.exe!__scrt_common_main()
    D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_main.cpp (17): app.exe!mainCRTStartup()
    KERNEL32.DLL!BaseThreadInitThunk() + 0x17 bytes
    ntdll.dll!RtlUserThreadStart() + 0x2C bytes
  Data:
    7B 00 32 00    38 00 66 00    62 00 62 00    35 00 34 00     {.2.8.f. b.b.5.4.
    31 00 2D 00    66 00 63 00    65 00 65 00    2D 00 34 00     1.-.f.c. e.e.-.4.
    30 00 62 00    36 00 2D 00    62 00 34 00    33 00 34 00     0.b.6.-. b.4.3.4.
    2D 00 32 00    64 00 31 00    66 00 38 00    30 00 38 00     -.2.d.1. f.8.0.8.
    36 00 62 00    64 00 65 00    34 00 7D 00    00 00           6.b.d.e. 4.}.....


Visual Leak Detector detected 37 memory leaks (2232 bytes).
Largest number used: 11387 bytes.
Total allocations: 50233 bytes.
Visual Leak Detector is now exiting.