Getting Connection-State from Bluetooth Low Energy Device from Device Manager - c++

Question

i'm developing on a Bluetooth Low Energy Device and i need to see in code if the device is connected or not.
First thing i noticed was that there is in the Devicemanager a Attribute "Verbunden"-> English: Connected and it says true or false if my device is connected or not. So i need to read that Attribute in my program.
What i have tried till now:
Getting all Devices with SetupDiGetClassDevs
Getting the FriendlyName with SetupDiGetDeviceRegistryProperty
Searching for my Device with the name.
That works.
Now i wanted to get that Connected-Attribute but i didn't find out what i have to use at SetupDiGetDeviceRegistryProperty.
SetupDiGetDeviceRegistryProperty is described here https://msdn.microsoft.com/en-us/library/windows/hardware/ff551967(v=vs.85).aspx
Maybe someone knows what is the right value for Property.
My Code:
int get_device_info( void )
{
HDEVINFO hDevInfo;
SP_DEVINFO_DATA DeviceInfoData;
DWORD i;
FILE * devices = fopen("devices.txt", "a+");
GUID AGuid;
//GUID can be constructed from "{xxx....}" string using CLSID
CLSIDFromString(TEXT(TO_SEARCH_DEVICE_UUID), &AGuid);
GUID BluetoothInterfaceGUID = AGuid;
// Create a HDEVINFO with all present devices.
hDevInfo = SetupDiGetClassDevs(&BluetoothInterfaceGUID,
0, // Enumerator
0,
DIGCF_ALLCLASSES | DIGCF_PRESENT);
if (hDevInfo == INVALID_HANDLE_VALUE)
{
// Insert error handling here.
return 1;
}
// Enumerate through all devices in Set.
DeviceInfoData.cbSize = sizeof(SP_DEVINFO_DATA);
for (i=0;SetupDiEnumDeviceInfo(hDevInfo,i,
&DeviceInfoData);i++)
{
DWORD DataT;
LPTSTR buffer = NULL;
DWORD buffersize = 0;
//
// Call function with null to begin with,
// then use the returned buffer size (doubled)
// to Alloc the buffer. Keep calling until
// success or an unknown failure.
//
// Double the returned buffersize to correct
// for underlying legacy CM functions that
// return an incorrect buffersize value on
// DBCS/MBCS systems.
//
while (!SetupDiGetDeviceRegistryProperty(
hDevInfo,
&DeviceInfoData,
SPDRP_FRIENDLYNAME,
//SPDRP_DEVICEDESC,
//SPDRP_CAPABILITIES,
&DataT,
(PBYTE)buffer,
buffersize,
&buffersize))
{
if (GetLastError() ==
ERROR_INSUFFICIENT_BUFFER)
{
// Change the buffer size.
if (buffer) LocalFree(buffer);
// Double the size to avoid problems on
// W2k MBCS systems per KB 888609.
buffer = (wchar_t *)LocalAlloc(LPTR,buffersize * 2);
}
else
{
// Insert error handling here.
break;
}
}
if(buffer)
{
if( strcmp("Name of Device",AnsiString(buffer).c_str())==0)
{
fprintf(devices,"Result:[%s]",AnsiString(buffer).c_str());
if (buffer) LocalFree(buffer);
}
}
}
if ( GetLastError()!=NO_ERROR &&
GetLastError()!=ERROR_NO_MORE_ITEMS )
{
// Insert error handling here.
return 1;
}
// Cleanup
SetupDiDestroyDeviceInfoList(hDevInfo);
fclose(devices);
return 0;
}

Answer 1

Instead of using SetupDiEnumDeviceInfo, you would try:
1. using SetupDiEnumDeviceInterfaces
2. using SetupDiGetDeviceInterfaceProperty
3. using SetupDiGetDeviceInterfacePropertyKeys to get a list of all Property Keys available for the interface
4. using SetupDiGetDeviceProperty and/or SetupDiGetDeviceRegistryProperty
Instead of using SPDRP_XXX constants, you would use DEVPROP, as defined in 'devpkey.h' ...
Below are a few examples taken from the log of a test prog I wrote to discover the whole thing:
DEVPROPNAME: DEVPKEY_DeviceInterface_Bluetooth_DeviceAddress
DEVPROPGUID: {2BD67D8B-8BEB-48D5-87E0-6CDA3428040A}
DEVPROPPID: 1
DEVPROPTYPE: DEVPROP_TYPE_STRING
Value: c026df001017
DEVPROPNAME: DEVPKEY_Device_Children
DEVPROPGUID: {4340A6C5-93FA-4706-972C-7B648008A5A7}
DEVPROPPID: 9
DEVPROPTYPE: DEVPROP_TYPE_STRING_LIST
Value:
BTHLEDevice\{00001800-0000-1000-8000-00805f9b34fb}_c026df001017\8&2fd07168&1&0001
BTHLEDevice\{00001801-0000-1000-8000-00805f9b34fb}_c026df001017\8&2fd07168&1&0008
BTHLEDevice\{00001809-0000-1000-8000-00805f9b34fb}_c026df001017\8&2fd07168&1&000c
BTHLEDevice\{0000180f-0000-1000-8000-00805f9b34fb}_c026df001017\8&2fd07168&1&0010
BTHLEDevice\{0000180a-0000-1000-8000-00805f9b34fb}_c026df001017\8&2fd07168&1&0014
BTHLEDevice\{00001523-1212-efde-1523-785feabcd123}_c026df001017\8&2fd07168&1&0019
On a second subject, you are 'working' on the 'device' itself ( SetupDiGetClassDevs(&BluetoothInterfaceGUID...) [and then working on the \BTHLE\ tree in Registry].
After listing all GattServices of this device and getting their uuids, you could restart that iteration on the device_guid itself SetupDiGetClassDevs(&GattServiceGUID...) [and then working on the \BTHLEDevice\ tree in Registry].
Now, to answer your question, I'm still searching myself :) But I'm not really sure:
1) that it is a working (dynamic) information to know the connection state
2) that it is a 'Property' you can access by the above methods

Answer 2

I have found out a solution.
GUID AGuid;
//GUID can be constructed from "{xxx....}" string using CLSID
CLSIDFromString(TEXT(TO_SEARCH_DEVICE_UUID), &AGuid);
GUID BluetoothInterfaceGUID = AGuid;
// Create a HDEVINFO with all present devices.
hDevInfo = SetupDiGetClassDevs(&BluetoothInterfaceGUID,
0, // Enumerator
0,
DIGCF_ALLCLASSES | DIGCF_PRESENT);//DIGCF_DEVICEINTERFACE | DIGCF_PRESENT);//DIGCF_ALLCLASSES | DIGCF_PRESENT);
if (hDevInfo == INVALID_HANDLE_VALUE)
{
// Insert error handling here.
return 1;
}
// Enumerate through all devices in Set.
DeviceInfoData.cbSize = sizeof(SP_DEVINFO_DATA);
for (i=0;SetupDiEnumDeviceInfo(hDevInfo,i,
&DeviceInfoData);i++)
{
DWORD DataT;
LPTSTR buffer = NULL;
LPTSTR buffer1 = NULL;
DWORD buffersize = 0;
while (!SetupDiGetDeviceRegistryProperty( // Get Name
hDevInfo,
&DeviceInfoData,
SPDRP_FRIENDLYNAME,
&DataT,
(PBYTE)buffer,
buffersize,
&buffersize))
{
if (GetLastError() ==
ERROR_INSUFFICIENT_BUFFER)
{
// Change the buffer size.
if (buffer) LocalFree(buffer);
// Double the size to avoid problems on
// W2k MBCS systems per KB 888609.
buffer = (wchar_t *)LocalAlloc(LPTR,buffersize * 2);
}
else
{
// Insert error handling here.
break;
}
}
{
if(strcmp("Your Device",AnsiString(buffer).c_str())==0) //Found your device
{
//########
DEVPROPTYPE ulPropertyType;
DWORD dwSize;
ULONG devst;
// memset(devst,0,sizeof(devst));
bool err = SetupDiGetDeviceProperty( //Checking Connection State
hDevInfo,
&DeviceInfoData,
&DEVPKEY_Device_DevNodeStatus, //Connected(0x02000000)
&ulPropertyType,
(BYTE *) &devst,
sizeof(devst),
&dwSize,
0);
DWORD error;
error = GetLastError();
if (devst &0x02000000) {
//"Status: Getrennt "
}
else
{
//"Status: Verbunden"
}
Hope this snippet helps.