IOCTL_BTHHFP_DEVICE_GET_DESCRIPTOR IOCTL (bthhfpddi.h)
The audio driver issues the IOCTL_BTHHFP_DEVICE_GET_DESCRIPTOR control code to get information about an enabled GUID_DEVINTERFACE_BLUETOOTH_HFP_SCO_HCIBYPASS device interface.
Major code
Input buffer
None.
Input buffer length
None.
Output buffer
A buffer containing a BTHHFP_DESCRIPTOR structure followed by any other data referenced by the structure. This is true, if the output buffer size is sufficient and the request succeeds. In particular, the buffer includes storage for the string referenced by the FriendlyName field of the BTHHFP_DESCRIPTOR structure.
Output buffer length
The size of a BTHHFP_DESCRIPTOR structure and referenced data.
Status block
If the routine succeeds, then Status is set to STATUS_SUCCESS and the Information member is the number of bytes that the routine writes to the output buffer.
Remarks
The audio driver sends this request to obtain information about an enabled GUID_DEVINTERFACE_BLUETOOTH_HFP_SCO_HCIBYPASS device interface. The information does not change while the interface is enabled, but can change while the interface is disabled. Therefore the audio driver sends this request shortly after discovering an enabled device interface and uses the information to build an appropriate KSFILTER_DESCRIPTOR structure.
The audio driver sends this request once with an output buffer size of zero (0) in order to determine the required output buffer size. In this case, the request will complete with Status STATUS_BUFFER_TOO_SMALL and set the Information member to the required buffer size. The audio driver then allocates the necessary storage space and sends the request again. Typically an audio driver will store a pointer to this storage location in its device context for reference during later activity.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 8 |
| Minimum supported server | Windows Server 2012 |
| Header | bthhfpddi.h |