How to Detect Usb Device Disconnect Under Linux/Qt/C++

Is there a Qt solution for detecting USB events (insertion and removal)?

As already pointed out, Qt itself does not provide such a module. There is however a user-made class called QDeviceWatcher. I have no experience with it personally and it is not updated regularly but you could give it a try.

You can find the forum post here and the git repository here.

How to bind to connect/disconnect USB device event in windows 7/8/10 from Qt

Thanks to @kunif I've found solution. So to listen to Windows messages you need to add your own EventFilter by inheriting QAbstractNativeEventFilter like this:

#include <QAbstractNativeEventFilter>
#include <QObject>

class DeviceEventFilter : public QObject, public QAbstractNativeEventFilter
{
    Q_OBJECT

public:
    DeviceEventFilter();
    bool nativeEventFilter(const QByteArray &eventType, void *message, long *) override;

signals:
    void serialDeviceChanged();
};

And filter the message you need WM_DEVICECHANGE:

#include <windows.h>
#include <dbt.h>

bool DeviceEventFilter::nativeEventFilter(const QByteArray &eventType, void *message, long *) {
    if (eventType == "windows_generic_MSG") {
        MSG *msg = static_cast<MSG *>(message);

        if (msg->message == WM_DEVICECHANGE) {
            if (msg->wParam == DBT_DEVICEARRIVAL || msg->wParam == DBT_DEVICEREMOVECOMPLETE) {
                // connect to this signal to reread available ports or devices etc
                emit serialDeviceChanged();        
            }
        }
    }
    return false;
}

And somewhere in your code, where you have access to DeviceEventFilter object add this line:

qApp->installNativeEventFilter(&devEventFilterObj);

Or in main.cpp :

QApplication app(argc, argv);
app.installNativeEventFilter(&devEventFilterObj);

All gratitude to @kunif !

Detecting USB mouse. Qt on Embedded Linux

Qt itself does not provide such a module. There is a user-made class called QDeviceWatcher, you could give it a try.

If you are using QtEmbedded Linux, you have a folder with all USB devices info (vendor id, etc), probably in /proc/scsi/usb-storage file. So you probably could use QFileSystemWatcher to handle modification in this folder.

See: Qt Centre Post for more detail.

How to get path to USB drive on Linux in Qt?

I found this code to do exactly what I need:

foreach (const QStorageInfo &storage, QStorageInfo::mountedVolumes()) {

   qDebug() << storage.rootPath();
   if (storage.isReadOnly())
       qDebug() << "isReadOnly:" << storage.isReadOnly();

   qDebug() << "name:" << storage.name();
   qDebug() << "fileSystemType:" << storage.fileSystemType();
   qDebug() << "size:" << storage.bytesTotal()/1000/1000 << "MB";
   qDebug() << "availableSize:" << storage.bytesAvailable()/1000/1000 << "MB";
}

Output:

"/run"
name: ""
fileSystemType: "tmpfs"
size: 6748 MB
availableSize: 6729 MB
"/"
name: ""
fileSystemType: "ext4"
size: 64370 MB
availableSize: 22236 MB
"/run/lock"
name: ""
fileSystemType: "tmpfs"
size: 5 MB
availableSize: 5 MB
"/home"
name: ""
fileSystemType: "ext4"
size: 183169 MB
availableSize: 27305 MB
"/run/user/1000"
name: ""
fileSystemType: "tmpfs"
size: 6748 MB
availableSize: 6748 MB
"/media/superuser/Backups"
name: "Backups"
fileSystemType: "ext4"
size: 252113 MB
availableSize: 133173 MB
"/media/superuser/Data"
name: "Data"
fileSystemType: "ext4"
size: 732123 MB
availableSize: 694298 MB
"/media/superuser/BackupWD"
name: "BackupWD"
fileSystemType: "fuseblk"
size: 209713 MB
availableSize: 13144 MB
"/media/superuser/WDSpace"
name: "WDSpace"
fileSystemType: "fuseblk"
size: 790484 MB
availableSize: 582583 MB

How can I detect a USB disconnect event? (Windows, .NET C# application)

I ended up using this: http://msdn.microsoft.com/en-us/library/aa363480(VS.85).aspx

And followed this: http://www.codeproject.com/KB/system/DriveDetector.aspx

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