Hello, I want to use bluetooth to scan other devices, but don't want other devices can see windows pc. I found that if "allow bluetooth devices to find this pc" is checked, other devices can also find windows pc at any time. So how to make the "allow bluetooth devices to find this pc" unchecked or just let windows do not broadcast self with windows api or shell scripts ? (do manual work to set it in system settings is not acceptable because IT can not deploy it widely) BTW , I have tried BluetoothEnableDiscovery(NULL, false) , but it is can not work successfully when "allow bluetooth devices to find this pc" is checked... Thanks.

How to uncheck the click"allow bluetooth devices to find this pc" by windows api?

Accepted answer

Castorix31 81,636

With BluetoothFindFirstRadio and so on then DeviceIoControl with 0x411020 code

(some details at https://refcount.blogspot.com/2021/09/behind-bthportsys.html)

frank zhang 121

Thanks, I tried it and it seems work, though the clickbox is still checked after I call ScanEnable(hRadio, 0), but windows pc trully did not broadcast it self !!!

Could you show some details/docs about magic code 0x103 and 0x411020 ？ I did not find them on internet. thanks.

My code:

int ScanEnable(HANDLE hRadio, unsigned char bEnable)
{
    unsigned short scanFlags[2];
    DWORD returned;
    scanFlags[0] = 0x0103; // what is this magic code? 
    scanFlags[1] = bEnable & 1;
    return DeviceIoControl(hRadio,
                           0x411020, // what is this magic code?
                           scanFlags, sizeof(scanFlags),
                           NULL, 0,
                           &returned, NULL);
}

int main() {
....

    BLUETOOTH_RADIO_INFO radioInfo;
    HANDLE hradio;
    BLUETOOTH_FIND_RADIO_PARAMS btfrp = {sizeof(BLUETOOTH_FIND_RADIO_PARAMS)};
    HBLUETOOTH_RADIO_FIND hFind = BluetoothFindFirstRadio(&btfrp, &hradio);
    hFind = BluetoothFindFirstRadio(&btfrp, &hradio);
    if (!hFind)
    {
        printf("Hfind failed\n");
        return -1;
    }
    else
        printf("Hfind success\n");
    int res = ScanEnable(hradio, 0); // try to uncheck it.
    if(res != 0) {
        printf("set success, res=%d\n", res);
    } else {
        printf("set failed, err=%d\n", GetLastError);
    }
...

}

Castorix31 81,636 Reputation points

2023-04-03T09:11:37.6466667+00:00

Could you show some details/docs about magic code 0x103 and 0x411020 ？ I did not find them on internet. thanks.

They are not documented

They can be found by debugging/api hooking (WinDbg Preview or other tools)

How to uncheck the click"allow bluetooth devices to find this pc" by windows api?

0 additional answers