Detecting USB notification in Qt on windows - winapi

Question

In my qt application I want to save some application output data to an file in my usb pen drive. I need to put following features in my qt application
Detect the usb drive insertion
I have only one usb slot.
After i insert it I want to know its drive number and letter and transfer a file at specific location in my PC to that usb drive.
Can anybody tell me which winapi .lib , .h and .dll file i hav to use to get all the above functionalities ?
If someone can provide some code snippets, it will very much helpful for me.

Answer 1

Handle WM_DEVICECHANGE - See http://lists.trolltech.com/qt-interest/2001-08/thread00698-0.html for how to handle windows messages in QT.
If wParam is DBT_DEVICEARRIVAL then cast lParam to a DEV_BROADCAST_HDR *
If the structures dbch_devicetype is DBT_DEVTYP_VOLUME cast lParam again, this time to a DEV_BROADCAST_VOLUME *
Now check the dbcv_unitmask bit field, iterate over bits 0..31 and check if the corresponding drive match your USB drive.
if (wParam == DBT_DEVICEARRIVAL) {
if (((DEV_BROADCAST_HDR *) lParam)->dbch_devicetype == DBT_DEVTYP_VOLUME) {
DWORD Mask = ((DEV_BROADCAST_VOLUME *) lParam)->dbcv_unitmask;
for (int i = 0; i < 32; ++i) {
if (Mask & (1 << i)) {
char RootPath[4] = "A:\\";
RootPath[0] += i;
// Check if the root path in RootPath is your USB drive.
}
}
}
}

Answer 2

The earlier answer is now out-of-date. The following worked for me with QT5 on Windows 10, where MainWindow is derived from QMainWindow:
#include <QByteArray>
#include <windows.h>
#include <dbt.h>
bool MainWindow::nativeEvent(const QByteArray& eventType, void* pMessage, long* pResult)
{
auto pWindowsMessage = static_cast<MSG*>(pMessage);
auto wParam = pWindowsMessage->wParam;
if (wParam == DBT_DEVICEARRIVAL || wParam == DBT_DEVICEREMOVECOMPLETE) {
auto lParam = pWindowsMessage->lParam;
auto deviceType = reinterpret_cast<DEV_BROADCAST_HDR*>(lParam)->dbch_devicetype;
if (deviceType == DBT_DEVTYP_VOLUME) {
auto unitmask = reinterpret_cast<DEV_BROADCAST_VOLUME*>(lParam)->dbcv_unitmask;
for (int i = 0; i < 32; ++i) {
if ((unitmask & (1 << i)) != 0) {
setDriveChanged('A' + i, wParam == DBT_DEVICEARRIVAL);
}
}
}
}
return false;
}