### virtual kern_return_t Start(IOService *provider)

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiodriver/start

Starts the current service and associates it with the specified provider.

```APIDOC
## Start

### Description
Starts the current service and associates it with the specified provider. This method is called after the system matches the provider to the driver's service.

### Method
Instance Method

### Parameters
#### Path Parameters
- **provider** (IOService*) - Required - The provider object that matches the current service.

### Return Value
- **kern_return_t** - kIOReturnSuccess on success, or another value if an error occurs.

### Discussion
Override this method inherited from IOService. Use this method to configure driver data structures and setup associated hardware. Call RegisterService after configuration to indicate the service is running. Always call super early in the implementation.
```

--------------------------------

### StartIO Method

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiodevice/startio

Tells the device to start I/O operations.

```APIDOC
## StartIO

### Description
Tells the device to start I/O. Subclass and override this method to handle hardware-specific tasks during I/O startup.

### Method
Instance Method

### Parameters
- **in_flags** (IOUserAudioStartStopFlags) - Required - A flag to indicate I/O startup behavior.

### Return Value
- **kIOReturnSuccess** (kern_return_t) - Returned on success, or another value if an error occurs.
```

--------------------------------

### StartIO Method

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudioclockdevice/startio

Tells the clock device to start I/O operations.

```APIDOC
## StartIO

### Description
Tells the clock device to start I/O.

### Method
virtual kern_return_t

### Parameters
- **in_flags** (IOUserAudioStartStopFlags) - Required - A value to indicate I/O startup behavior.

### Return Value
- **kIOReturnSuccess** (kern_return_t) - Returned on success, or another value if an error occurs.

### Discussion
The default implementation always returns kIOReturnSuccess. Subclass and override this method to handle hardware-specific tasks during I/O startup, then call the superclass to update the I/O state.
```

--------------------------------

### Instance Method: init

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiodriver/init

Handles the basic initialization of the service. This method is called shortly after your custom IOService subclass is instantiated and before the Start method is called. It's suitable for simple tasks that must occur before the service starts, such as allocating memory.

```APIDOC
## Instance Method: init

### Description
Handles the basic initialization of the service. Override this method inherited from `IOService`. The system calls this method shortly after it instantiates your custom `IOService` subclass, and before it calls the `Start` method of your service. Limit the work you do in this method to simple tasks that must occur before your service starts. For example, use this method to allocate memory for your `ivars` structure. Always call `super` early in your implementation of this method.

### Method
```cpp
virtual bool init();
```

### Return Value
`true` if initialization was successful, or `false` if an error occurred.

### See Also
- `Start`
- `Stop`
- `free`
```

--------------------------------

### Implement StartIO for AudioDriverKit

Source: https://developer.apple.com/documentation/audiodriverkit/creating-an-audio-device-driver

Handles the start of audio I/O by mapping memory descriptors and initializing timers.

```cpp
kern_return_t SimpleAudioDevice::StartIO(IOUserAudioStartStopFlags in_flags)
{
	DebugMsg("Start I/O: device %u", GetObjectID());
	
	__block kern_return_t error = kIOReturnSuccess;
	__block OSSharedPtr<IOMemoryDescriptor> input_iomd;
	__block OSSharedPtr<IOMemoryDescriptor> output_iomd;


	ivars->m_work_queue->DispatchSync(^(){
		//	Tell IOUserAudioObject base class to start I/O for the device.
		error = super::StartIO(in_flags);
		FailIfError(error, , Failure, "Failed to start I/O");
		
		output_iomd = ivars->m_output_stream->GetIOMemoryDescriptor();
		FailIfNULL(output_iomd.get(), error = kIOReturnNoMemory, Failure, "Failed to get output stream IOMemoryDescriptor");
		error = output_iomd->CreateMapping(0, 0, 0, 0, 0, ivars->m_output_memory_map.attach());
		FailIf(error != kIOReturnSuccess, , Failure, "Failed to create memory map from output stream IOMemoryDescriptor");
		
		input_iomd = ivars->m_input_stream->GetIOMemoryDescriptor();
		FailIfNULL(input_iomd.get(), error = kIOReturnNoMemory, Failure, "Failed to get input stream IOMemoryDescriptor");
		error = input_iomd->CreateMapping(0, 0, 0, 0, 0, ivars->m_input_memory_map.attach());
		FailIf(error != kIOReturnSuccess, , Failure, "Failed to create memory map from input stream IOMemoryDescriptor");


		// Start the timers to send timestamps and generate sine tone on the stream I/O buffer.
		StartTimers();
		return;
		
	Failure:
		super::StopIO(in_flags);
		ivars->m_output_memory_map.reset();
		ivars->m_input_memory_map.reset();
		return;
	});


	return error;
}
```

--------------------------------

### StartDevice Method Signature

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiodriver/startdevice

Defines the virtual method for starting I/O on a specified audio object.

```cpp
virtual kern_return_t StartDevice(IOUserAudioObjectID in_object_id, IOUserAudioStartStopFlags in_flags);
```

--------------------------------

### GetStartingChannel Instance Method

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiostream/getstartingchannel

Retrieves the starting channel index for the audio driver.

```APIDOC
## GetStartingChannel

### Description
Retrieves the starting channel index for the audio driver.

### Method
Instance Method

### Endpoint
N/A (Instance Method)

### Parameters
None

### Request Example
N/A

### Response
#### Success Response (uint32_t)
- Returns the starting channel index as a 32-bit unsigned integer.

#### Response Example
```
uint32_t startingChannel = GetStartingChannel();
```
```

--------------------------------

### Instance Method: StartIO

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiostream/startio

Tells the stream to start I/O. This method can be overridden by subclasses to handle hardware-specific tasks during I/O startup.

```APIDOC
## Instance Method: StartIO

### Description
Tells the stream to start I/O.

### Method
`virtual kern_return_t StartIO(IOUserAudioStartStopFlags in_flags);`

### Endpoint
N/A (Instance Method)

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
None

### Response
#### Success Response (kIOReturnSuccess)
`kIOReturnSuccess` on success.

#### Error Response
Another `kern_return_t` value if an error occurs. For a list of error codes, see Error Codes.

#### Response Example
`kIOReturnSuccess`

### Discussion
The default implementation always returns `kIOReturnSuccess`. Subclass and override this method to handle hardware-specific tasks during I/O startup, then call the superclass to update the I/O state. The framework expects this call to always succeed or fail. The hardware can take as long as it needs in this call, provided it always either succeeds or fails.

### See Also
- `StopIO`
- `IOUserAudioStartStopFlags`
```

--------------------------------

### Start Service Implementation

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiodriver/start

Override this method to configure driver data structures and hardware. Always call the super implementation early.

```cpp
virtual kern_return_t Start(IOService *provider);
```

--------------------------------

### Implement AudioDriverKit Driver Start Method

Source: https://developer.apple.com/documentation/audiodriverkit/creating-an-audio-device-driver

This C++ code implements the Start_Impl method for a custom AudioDriverKit driver. It initializes and configures a virtual audio device, registers it with the system, and handles potential errors during the process. Ensure necessary entitlements are configured for hardware communication if not using a virtual device.

```cpp
kern_return_t SimpleAudioDriver::Start_Impl(IOService* in_provider)
{
	bool success = false;
	auto device_uid = OSSharedPtr(OSString::withCString(kSimpleAudioDriverDeviceUID), OSNoRetain);
	auto model_uid = OSSharedPtr(OSString::withCString("SimpleAudioDevice-Model"), OSNoRetain);
	auto manufacturer_uid = OSSharedPtr(OSString::withCString("Apple Inc."), OSNoRetain);
	auto device_name = OSSharedPtr(OSString::withCString("SimpleAudioDevice"), OSNoRetain);
	
kern_return_t error = Start(in_provider, SUPERDISPATCH);
	FailIfError(error, , Failure, "Failed to start Super");
	
	// Get the service's default dispatch queue from the driver object.
	ivars->m_work_queue = GetWorkQueue();
	FailIfError(ivars->m_work_queue.get() == nullptr, error = kIOReturnInvalid, Failure, "failed to get default work queue");
		
	// Allocate and configure audio devices as necessary.
	ivars->m_simple_audio_device = OSSharedPtr(OSTypeAlloc(SimpleAudioDevice), OSNoRetain);
	FailIfNULL(ivars->m_simple_audio_device.get(), error = kIOReturnNoMemory, Failure, "Failed to allocate SimpleAudioDevice");
	
	success = ivars->m_simple_audio_device->init(this, false, device_uid.get(), model_uid.get(), manufacturer_uid.get(), k_zero_time_stamp_period);
	FailIf(success == false, error = kIOReturnNoMemory, Failure, "Failed to init SimpleAudioDevice");
	
	ivars->m_simple_audio_device->SetName(device_name.get());
	
	// Add the device object to the driver.
	AddObject(ivars->m_simple_audio_device.get());
		
	// Register the service.
	error = RegisterService();
	FailIfError(error, , Failure, "failed to register service!");
	
	return kIOReturnSuccess;
	
Failure:
	return error;
}

```

--------------------------------

### Instance Method: StartDevice

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiodriver/startdevice

Tells the driver to start I/O on an audio device or audio clock device. This method is available in DriverKit 21.0 and later.

```APIDOC
## StartDevice

### Description
Tells the driver to start I/O on an audio device or audio clock device.

### Method
```cpp
virtual kern_return_t StartDevice(IOUserAudioObjectID in_object_id, IOUserAudioStartStopFlags in_flags);
```

### Parameters
#### Path Parameters
- None

#### Query Parameters
- None

#### Request Body
- None

### Parameters
`in_object_id` (IOUserAudioObjectID) - Required - The identifier of the device on which to start I/O.
`in_flags` (IOUserAudioStartStopFlags) - Required - A flag that indicates how to perform the I/O start operation.

### Request Example
- None

### Response
#### Success Response (kIOReturnSuccess)
- `kIOReturnSuccess` on success, or another value if an error occurs. For a list of error codes, see Error Codes.

#### Response Example
- None

### Discussion
The default implementation always returns `kIOReturnSuccess`. Subclass and override this method to handle hardware-specific startup, then call the superclass to update the I/O state. The framework expects this call to always succeed or fail. The hardware can take as long as it needs in this call, provided it always either succeeds or fails. This call results in a call to `StartIO` on the device.

### See Also
- `StopDevice`
- `IOUserAudioObjectID`
- `IOUserAudioStartStopFlags`
```

--------------------------------

### SetStartingChannel Method

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiostream/setstartingchannel

Sets the starting channel for the audio stream.

```APIDOC
## SetStartingChannel

### Description
Sets the starting channel for the IOUserAudioStream.

### Method
Instance Method

### Parameters
#### Parameters
- **in_starting_channel** (uint32_t) - Required - The starting channel index for the stream.

### Response
- **kern_return_t** - Returns the status of the operation.
```

--------------------------------

### SetStartingChannel Instance Method

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiostream/setstartingchannel

Use this method to set the starting channel for an audio stream. Requires DriverKit 21.0+.

```c
kern_return_t SetStartingChannel(uint32_t in_starting_channel);
```

--------------------------------

### GetStartingChannel Method Signature

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiostream/getstartingchannel

Retrieves the starting channel index for the audio stream. Available in DriverKit 21.0 and later.

```cpp
uint32_t GetStartingChannel();
```

--------------------------------

### Initialize AudioDriverKit Service

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiodriver/init

Override this method to perform basic initialization tasks before the service starts. Always call `super` early in your implementation. This method is called shortly after your custom `IOService` subclass is instantiated.

```cpp
virtual bool init();
```

--------------------------------

### Performing I/O Operations

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiodevice

Methods to start and stop I/O operations for the audio device.

```APIDOC
## Performing I/O

### `StartIO`
Tells the device to start I/O.

### `StopIO`
Tells the device to stop I/O.

### `IOUserAudioStartStopFlags`
Values that indicate I/O starts or stops.
```

--------------------------------

### Working with Default Device Behavior

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiodevice

Methods to set and get whether the device can be a default input or output device.

```APIDOC
## Working with Default Device Behavior

### `SetCanBeDefaultInputDevice`
Sets a Boolean value that indicates if this device can be the host’s default input device.

### `CanBeDefaultInputDevice`
Returns a Boolean value that indicates if this device can be the host’s default input device.

### `SetCanBeDefaultOutputDevice`
Sets a Boolean value that indicates if this device can be the host’s default output device.

### `CanBeDefaultOutputDevice`
Returns a Boolean value that indicates if this device can be the host’s default output device.

### `SetCanBeDefaultSystemOutputDevice`
Sets a Boolean value that indicates if this device can be the system’s default output device.

### `CanBeDefaultSystemOutputDevice`
Returns a Boolean value that indicates if this device can be the system’s default output device.
```

--------------------------------

### Update Timestamps and Start Timer

Source: https://developer.apple.com/documentation/audiodriverkit/creating-an-audio-device-driver

Updates the zero timestamp values and schedules the timer for the next callback.

```cpp
// Clear the device's timestamps.
UpdateCurrentZeroTimestamp(0, 0);
auto current_time = mach_absolute_time();


// Start the timer. The first timestamp occurs when the timer goes off.
ivars->m_zts_timer_event_source->WakeAtTime(kIOTimerClockMachAbsoluteTime, current_time + ivars->m_zts_host_ticks_per_buffer, 0);
ivars->m_zts_timer_event_source->SetEnable(true);
```

--------------------------------

### Get Preferred Stereo Channels - AudioDriverKit

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiodevice/getpreferredchannelsforstereo

Call this method to get the channel indices for the preferred stereo pair. Ensure you are using DriverKit 21.0 or later.

```c
void GetPreferredChannelsForStereo(uint32_t *out_left_channel, uint32_t *out_right_channel);
```

--------------------------------

### GET GetObjectID

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudioobject/getobjectid

Retrieves the unique identifier for an IOUserAudioObject instance.

```APIDOC
## GetObjectID

### Description
Gets the object’s identifier.

### Method
Instance Method

### Return Value
- **IOUserAudioObjectID** - The object’s identifier.

### Discussion
Use this identifier when looking up a driver’s objects with GetAudioObjectForObjectID.
```

--------------------------------

### Getting Information About the Class

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudioselectorcontrol

Methods for retrieving class identification information.

```APIDOC
### Getting Information About the Class

- `GetClassID`
  Gets the audio class identifier of the object.
- `GetBaseClassID`
  Gets the audio class identifier of the base class object.
```

--------------------------------

### StartIO Instance Method Signature

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudioclockdevice/startio

This is the signature for the StartIO instance method. Override this method to handle hardware-specific tasks during I/O startup. The framework expects this call to always succeed or fail.

```cpp
virtual kern_return_t StartIO(IOUserAudioStartStopFlags in_flags);
```

--------------------------------

### GET GetOwnerObjectID

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudioobject/getownerobjectid

Retrieves the object ID of the owner for an IOUserAudioObject instance.

```APIDOC
## GetOwnerObjectID

### Description
Retrieves the object ID of the owner for an IOUserAudioObject instance.

### Method
Instance Method

### Signature
IOUserAudioObjectID GetOwnerObjectID();

### Availability
DriverKit 21.0+
```

--------------------------------

### Initialize an IOUserAudioBox instance

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiobox/init

Initializes the audio box with the provided driver, acquirability status, and UID. The no-argument init method is not supported and will return false.

```cpp
virtual bool init(IOUserAudioDriver *in_driver, bool in_is_acquirable, OSString *in_box_uid);
```

--------------------------------

### GET GetScalarValue

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiolevelcontrol/getscalarvalue

Retrieves the current scalar value of the level control.

```APIDOC
## GET GetScalarValue

### Description
Gets the scalar value of the level control.

### Method
GET

### Endpoint
GetScalarValue

### Response
#### Success Response (200)
- **value** (float) - The scalar value of the level control.
```

--------------------------------

### Getting Information About the Class

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiodevice

Methods for retrieving class identifiers and information.

```APIDOC
## Getting Information About the Class

### `GetClassID`
Gets the audio class identifier of the object.

### `GetBaseClassID`
Gets the audio class identifier of the base class object.

### `IOUserAudioClassID`
An identifier for the type of audio object.
```

--------------------------------

### init Method Documentation

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiodevice/init

Initializes an instance of the audio device class within the DriverKit framework.

```APIDOC
## init

### Description
Initializes an instance of the audio device class.

### Method
Virtual Method

### Parameters
- **in_driver** (IOUserAudioDriver*) - Required - The IOUserAudioDriver that owns this object.
- **in_supports_prewarming** (bool) - Required - A Boolean value that specifies whether the device supports prewarming I/O.
- **in_device_uid** (OSString*) - Required - A pointer to an OSString containing the device UID.
- **in_model_uid** (OSString*) - Required - A pointer to an OSString containing the module UID.
- **in_manufacturer_uid** (OSString*) - Required - A pointer to an OSString containing the manufacturer UID.
- **in_zero_timestamp_period** (uint32_t) - Required - Indicates the number of sample frames the host can expect between successive timestamps returned from GetZeroTimeStamp().

### Return Value
- **bool** - true if initialization succeeded; false otherwise.
```

--------------------------------

### Create an IOUserAudioBox instance

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiobox/create

Use this static method to allocate and initialize an audio box. Do not use this method when working with custom subclasses of IOUserAudioBox.

```cpp
static OSSharedPtr<IOUserAudioBox> Create(IOUserAudioDriver *in_driver, bool in_is_acquirable, OSString *in_box_uid);
```

--------------------------------

### GetBaseClassID

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiodriver/getbaseclassid

Gets the audio class identifier of the base class object.

```APIDOC
## GetBaseClassID

### Description
Gets the audio class identifier of the base class object.

### Method
Instance Method

### Endpoint
N/A (Instance Method)

### Parameters
N/A

### Request Example
N/A

### Response
#### Success Response
- **IOUserAudioClassID** (type) - The audio class identifier of the base class object.

#### Response Example
N/A
```

--------------------------------

### init Method

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiostereopancontrol/init

Initializes an instance of a stereo pan control.

```APIDOC
## init

### Description
Initializes an instance of a stereo pan control.

### Parameters
- **in_driver** (IOUserAudioDriver) - The IOUserAudioDriver that owns this object.
- **in_is_settable** (bool) - A Boolean value that indicates if the control can be set.
- **in_control_value** (float) - A floating-point value that represents the control’s current stereo pan value.
- **in_left_channel** (IOUserAudioObjectPropertyElement) - The IOUserAudioObjectPropertyElement for the left channel.
- **in_right_channel** (IOUserAudioObjectPropertyElement) - The IOUserAudioObjectPropertyElement for the right channel.
- **in_control_element** (IOUserAudioObjectPropertyElement) - An IOUserAudioObjectPropertyElement to identify the control.
- **in_control_scope** (IOUserAudioObjectPropertyScope) - A IOUserAudioObjectPropertyScope indicating the control’s scope: input, output, global, or play-through.
- **in_control_class_id** (IOUserAudioClassID) - The IOUserAudioClassID of the control.

### Return Value
- **bool** - true if initialization succeeded; false otherwise.
```

--------------------------------

### Get Current Client Sample Time

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudioclockdevice/getcurrentclientsampletime

Use this method to obtain the current input and output sample times that the client has written to or read from the ring buffer. Available in DriverKit 21.0+.

```c
void GetCurrentClientSampleTime(uint64_t *out_input_sample_time, uint64_t *out_output_sample_time);
```

--------------------------------

### Accessing the Value

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiobooleancontrol

Methods for setting and getting the Boolean value of the control.

```APIDOC
## Accessing the Value
### `SetControlValue`
Sets the Boolean value of the control.

### `GetControlValue`
Gets the Boolean value of the control.
```

--------------------------------

### GetSupportsPrewarming

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudioclockdevice/getsupportsprewarming

Returns a Boolean value that indicates the clock device's support for prewarming. A device that supports prewarming can enable a minimal state that allows it to be ready to start audio I/O immediately on demand. This method synchronizes by using the work queue created by the object.

```APIDOC
## GetSupportsPrewarming

### Description
Returns a Boolean value that indicates the clock device’s support for prewarming.

### Method
Instance Method

### Endpoint
N/A (Instance Method)

### Return Value
`bool` - `true` if the clock device supports prewarming; `false` otherwise.

### Discussion
A device that supports prewarming can enable a minimal state that allows it to be ready to start audio I/O immediately on demand. This method synchronizes by using the work queue created by the object.

### See Also
- `SetZeroTimeStampPeriod`
- `GetZeroTimestampPeriod`
- `SetOutputLatency`
- `GetOutputLatency`
- `SetInputLatency`
- `GetInputLatency`
```

--------------------------------

### GET /IOUserAudioBox/GetClassID

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiobox/getclassid

Retrieves the audio class identifier of the IOUserAudioBox object.

```APIDOC
## GET /IOUserAudioBox/GetClassID

### Description
Gets the audio class identifier of the object. This method overrides the base class IOUserAudioObject.

### Method
GET

### Endpoint
IOUserAudioBox/GetClassID

### Response
#### Success Response (200)
- **IOUserAudioClassID** (type) - The audio class identifier of the object.
```

--------------------------------

### Create IOUserAudioDevice Instance

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiodevice/create

Use this static method to allocate and initialize an instance of the audio device class. Ensure you provide all required parameters, including the owning driver, prewarming support, and various unique identifiers.

```c++
static OSSharedPtr<IOUserAudioDevice> Create(IOUserAudioDriver *in_driver, bool in_supports_prewarming, OSString *in_device_uid, OSString *in_model_uid, OSString *in_manufacturer_uid, uint32_t in_zero_timestamp_period);
```

--------------------------------

### GetClockAlgorithm

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudioclockdevice/getclockalgorithm

Gets the clock algorithm of the clock device. Available in DriverKit 21.0+.

```APIDOC
## GetClockAlgorithm

### Description
Gets the clock algorithm of the clock device.

### Method
Instance Method

### Endpoint
N/A (Instance Method)

### Parameters
None

### Request Example
None

### Response
#### Success Response
- **IOUserAudioClockAlgorithm** (IOUserAudioClockAlgorithm) - The clock algorithm of the clock device.

#### Response Example
```c
IOUserAudioClockAlgorithm algorithm = GetClockAlgorithm();
```

### Discussion
This method synchronizes by using the work queue created by the object.

### See Also
- `SetClockAlgorithm`
- `IOUserAudioClockAlgorithm`
- `SetClockIsStable`
- `GetClockIsStable`
```

--------------------------------

### init Method

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiolevelcontrol/init

Initializes an instance of a level control for an audio driver.

```APIDOC
## init

### Description
Initializes an instance of a level control.

### Method
Virtual Function

### Parameters
- **in_driver** (IOUserAudioDriver) - Required - The IOUserAudioDriver that owns this object.
- **in_is_settable** (bool) - Required - A Boolean value that indicates if the control can be set.
- **in_decibel_value** (float) - Required - A floating-point value that represents the level control’s current value in decibels.
- **in_decibel_range** (IOUserAudioLevelControlRange) - Required - A IOUserAudioLevelControlRange that describes the minimum and maximum values of the level control.
- **in_control_element** (IOUserAudioObjectPropertyElement) - Required - An IOUserAudioObjectPropertyElement to identify the control.
- **in_control_scope** (IOUserAudioObjectPropertyScope) - Required - A IOUserAudioObjectPropertyScope indicating the control’s scope: input, output, global, or play-through.
- **in_control_class_id** (IOUserAudioClassID) - Required - The IOUserAudioClassID of the control.

### Return Value
- **bool** - true if initialization succeeded; false otherwise.
```

--------------------------------

### init Method

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiostream/init

Initializes an instance of the audio stream class.

```APIDOC
## init

### Description
Initializes an instance of the audio stream class.

### Parameters
- **in_driver** (IOUserAudioDriver) - Required - The IOUserAudioDriver that owns this object.
- **in_direction** (IOUserAudioStreamDirection) - Required - A IOUserAudioStreamDirection for the stream’s direction: input or output.
- **in_io_memory_descriptor** (IOMemoryDescriptor) - Required - A pointer to a IOMemoryDescriptor. The stream maps the descriptor’s buffer to the Host for doing audio I/O.

### Return Value
- **bool** - true if initialization succeeded; false otherwise.
```

--------------------------------

### IOUserAudioControl init Method

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiocontrol/init

Initializes an instance of an audio control. Available in DriverKit 21.0+.

```APIDOC
## IOUserAudioControl init

### Description
Initializes an instance of an audio control.

### Method
`virtual bool init(IOUserAudioDriver *in_driver, bool in_is_settable, IOUserAudioObjectPropertyElement in_control_element, IOUserAudioObjectPropertyScope in_control_scope)`

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
None

### Response
#### Success Response (true)
- **bool** - `true` if initialization succeeded; `false` otherwise.

#### Response Example
```
true
```

### See Also
- `IOUserAudioDriver`
- `IOUserAudioObjectPropertyElement`
- `IOUserAudioObjectPropertyScope`
```

--------------------------------

### GetControlValue

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiostereopancontrol/getcontrolvalue

Gets the floating-point stereo pan value of the control. Available in DriverKit 21.0+.

```APIDOC
## GetControlValue

### Description
Gets the floating-point stereo pan value of the control.

### Method
Instance Method

### Endpoint
N/A (Instance Method)

### Parameters
None

### Request Example
N/A

### Response
#### Success Response
- **float** - The floating-point stereo pan value of the control.

#### Response Example
```
float stereoPanValue = GetControlValue();
```

### Discussion
This method synchronizes by using the work queue created by the object.

### See Also
- `SetControlValue`
- `SetPanningChannels`
- `GetPanningChannels`
```

--------------------------------

### Accessing Selected Values

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudioselectorcontrol

Methods for setting, getting, and managing selector values and their descriptions.

```APIDOC
### Accessing the Selected Values

- `SetCurrentSelectedValues`
  Sets the current selections of the selector.
- `GetCurrentSelectedValues`
  Gets the current selections of the selector.
- `GetControlValuesCount`
  Gets the number of available selector values.
- `AddControlValueDescriptions`
  Add value descriptions to the selector control.
- `RemoveControlValueDescriptions`
  Removes value descriptions from the selector control.
- `GetControlValueDescriptions`
  Gets value descriptions used by the selector control.
```

--------------------------------

### Instance Method: init

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudioobject/init-26qwx

Initializes an empty object. Available in DriverKit 21.0+.

```APIDOC
## Instance Method: init

### Description
Initializes an empty object.

### Method
`init()`

### Endpoint
N/A (Instance Method)

### Parameters
This method does not take any parameters.

### Request Body
N/A

### Response
#### Success Response (bool)
- **`true`**: Initialization succeeded.
- **`false`**: Initialization failed.

### Response Example
```
// Example of how the return value might be used:
bool success = [audioObject init];
if (success) {
    // Initialization successful
} else {
    // Initialization failed
}
```

### Discussion
This no-arg initializer always returns `false`.
```

--------------------------------

### GetControlValueDescriptions

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudioselectorcontrol/getcontrolvaluedescriptions

Gets value descriptions used by the selector control. Available in DriverKit 21.0+.

```APIDOC
## GetControlValueDescriptions

### Description
Gets value descriptions used by the selector control.

### Method
Instance Method

### Endpoint
N/A (Instance Method)

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
None

### Response
#### Success Response (200)
None (This is a method signature, not an API endpoint with a typical response)

#### Response Example
None

### Signature
```c
size_t GetControlValueDescriptions(IOUserAudioSelectorValueDescription *out_control_value_descriptions, size_t in_num_value_descriptions);
```

### Parameters
- **out_control_value_descriptions** (IOUserAudioSelectorValueDescription *) - A pointer to a buffer of type `IOUserAudioSelectorValueDescription`, with a size of `in_num_value_descriptions`. On return, this buffer contains the value descriptions.
- **in_num_value_descriptions** (size_t) - The number of descriptions in `out_control_value_descriptions`.

### Return Value
- **size_t** - The number of values populated in the `out_control_value_descriptions` buffer.

### Discussion
This method synchronizes by using the work queue created by the object.

### See Also
- `SetCurrentSelectedValues`
- `GetCurrentSelectedValues`
- `GetControlValuesCount`
- `IOUserAudioSelectorValue`
- `AddControlValueDescriptions`
- `RemoveControlValueDescriptions`
- `IOUserAudioSelectorValueDescription`
```

--------------------------------

### IOUserAudioBox init Method

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiobox/init

Initializes an instance of the audio box class. This method is available in DriverKit 21.0 and later.

```APIDOC
## IOUserAudioBox init

### Description
Initializes an instance of the audio box class.

### Method
`virtual bool init(IOUserAudioDriver *in_driver, bool in_is_acquirable, OSString *in_box_uid);`

### Endpoint
N/A (Instance Method)

### Parameters
#### Path Parameters
N/A

#### Query Parameters
N/A

#### Request Body
N/A

### Request Example
N/A

### Response
#### Success Response (true)
- `bool` - `true` if initialization succeeded; `false` otherwise.

#### Response Example
N/A

### Discussion
Always pass in the `IOUserAudioDriver` and arguments. The no-argument `IOUserAudioBox/init()` always returns `false`.

### See Also
- Creating an Audio Box (`Create`)
- `IOUserAudioDriver`
```

--------------------------------

### GET GetBaseClassID

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiodevice/getbaseclassid

Retrieves the audio class identifier of the base class object for an IOUserAudioDevice.

```APIDOC
## GET GetBaseClassID

### Description
Gets the audio class identifier of the base class object. This method overrides the base class IOUserAudioObject.

### Method
GET

### Endpoint
GetBaseClassID

### Response
- **IOUserAudioClassID** (type) - An identifier for the type of audio object.
```

--------------------------------

### GetCustomPropertyValueWithQualifier

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiocustomproperty/getcustompropertyvaluewithqualifier

Gets the custom property value for a given qualifier. Available in DriverKit 21.0+.

```APIDOC
## GetCustomPropertyValueWithQualifier

### Description
Gets the custom property value for a given qualifier.

### Method
`virtual kern_return_t GetCustomPropertyValueWithQualifier(OSObject *in_qualifier_data, OSObject **out_data);
`

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
None

### Response
#### Success Response (kIOReturnSuccess)
Returns `kIOReturnSuccess` on success, or another value if an error occurs.

#### Response Example
None

### Discussion
Use this method to get the custom property’s data value, optionally adding a qualifier to further refine the action. For example, if a given property exists on multiple devices, use a device identifier as the qualifier to indicate which device to get the value from.
The base class returns the custom property value set on the object without looking at contents of the qualifier data. If the returned value should depend on the qualifier, subclass `IOUserAudioCustomProperty` and override this method.

### See Also
- `SetQualifierAndDataValue`
- `GetCustomPropertyInfo`
- `IOUserAudioCustomPropertyInfo`
```

--------------------------------

### IOUserAudioLevelControl: free

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiolevelcontrol/free

Documentation for the free instance method used to release resources for the level control.

```APIDOC
## free

### Description
Frees the level control.

### Method
Instance Method

### Signature
`virtual void free();`

### Availability
DriverKit 21.0+
```

--------------------------------

### GetAvailableSampleRates

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudioclockdevice/getavailablesamplerates

Gets the available sample rates of the clock device. Available in DriverKit 21.0+.

```APIDOC
## GetAvailableSampleRates

### Description
Gets the available sample rates of the clock device.

### Method
Instance Method

### Endpoint
N/A (Instance Method)

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Parameters
`out_sample_rates` (double *) - Required - A pointer to a buffer of type `double` whose size corresponds to `in_num_rates`. After the call completes, this buffer contains the available sample rates.
`in_num_rates` (size_t) - Required - The number of rates in the `out_sample_rates` buffer.

### Return Value
A `size_t` that indicates how many rates were set in the `out_sample_rates` buffer.

### Discussion
This method synchronizes by using the work queue created by the object.

### See Also
* `SetSampleRate`
* `GetSampleRate`
* `SetAvailableSampleRates`
* `GetNumberAvailableSampleRates`
```

--------------------------------

### GetOutputLatency

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudioclockdevice/getoutputlatency

Gets the output latency of the clock device. Available in DriverKit 21.0 and later.

```APIDOC
## GetOutputLatency

### Description
Gets the output latency of the clock device.

### Method
Instance Method

### Endpoint
N/A (Instance Method)

### Parameters
None

### Request Example
N/A

### Response
#### Success Response
- **uint32_t**: The output latency of the clock device.

### Response Example
N/A (Method returns a value)

### Discussion
This method synchronizes by using the work queue created by the object.
```

--------------------------------

### Getting Information About the Class

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiobooleancontrol

Methods for retrieving class identification information for the IOUserAudioBooleanControl object.

```APIDOC
## Getting Information About the Class
### `GetClassID`
Gets the audio class identifier of the object.

### `GetBaseClassID`
Gets the audio class identifier of the base class object.
```

--------------------------------

### Create and Configure Audio I/O Buffers and Streams

Source: https://developer.apple.com/documentation/audiodriverkit/creating-an-audio-device-driver

Allocate shared memory for I/O ring buffers and create user audio stream objects for input and output. Configure stream properties like name, available formats, and current format.

```cpp
OSSharedPtr<IOBufferMemoryDescriptor> output_io_ring_buffer;
OSSharedPtr<IOBufferMemoryDescriptor> input_io_ring_buffer;
const auto buffer_size_bytes = static_cast<uint32_t>(in_zero_timestamp_period * sizeof(uint16_t) * channels_per_frame);
error = IOBufferMemoryDescriptor::Create(kIOMemoryDirectionInOut, buffer_size_bytes, 0, output_io_ring_buffer.attach());
FailIf(error != kIOReturnSuccess, , Failure, "Failed to create output IOBufferMemoryDescriptor");


error = IOBufferMemoryDescriptor::Create(kIOMemoryDirectionInOut, buffer_size_bytes, 0, input_io_ring_buffer.attach());
FailIf(error != kIOReturnSuccess, , Failure, "Failed to create input IOBufferMemoryDescriptor");


// Create an output/input stream object and pass in the I/O ring buffer memory descriptor.
ivars->m_output_stream = IOUserAudioStream::Create(in_driver, IOUserAudioStreamDirection::Output, output_io_ring_buffer.get());
FailIfNULL(ivars->m_output_stream.get(), error = kIOReturnNoMemory, Failure, "failed to create output stream");


ivars->m_input_stream = IOUserAudioStream::Create(in_driver, IOUserAudioStreamDirection::Input, input_io_ring_buffer.get());
FailIfNULL(ivars->m_input_stream.get(), error = kIOReturnNoMemory, Failure, "failed to create input stream");


//	Configure stream properties: name, available formats, and current format.
ivars->m_output_stream->SetName(output_stream_name.get());
ivars->m_output_stream->SetAvailableStreamFormats(stream_formats, 2);
ivars->m_stream_format = stream_formats[0];
ivars->m_output_stream->SetCurrentStreamFormat(&ivars->m_stream_format);


ivars->m_input_stream->SetName(input_stream_name.get());
ivars->m_input_stream->SetAvailableStreamFormats(stream_formats, 2);
ivars->m_input_stream->SetCurrentStreamFormat(&ivars->m_stream_format);


// Add a stream object to the driver.
error = AddStream(ivars->m_output_stream.get());
FailIfError(error, , Failure, "failed to add output stream");


error = AddStream(ivars->m_input_stream.get());
FailIfError(error, , Failure, "failed to add input stream");

```

--------------------------------

### Define IOUserAudioStartStopFlags Enumeration

Source: https://developer.apple.com/documentation/audiodriverkit/audiodriverkit/iouseraudiostartstopflags

The enumeration type used to indicate I/O start or stop states.

```C
enum IOUserAudioStartStopFlags : uint64_t;
```

--------------------------------

### Instance Methods

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiodevice

Additional instance methods available for the IOUserAudioDevice class.

```APIDOC
## Instance Methods

### `GetCurrentClientIOTime`

### `SetIOOperationHandler`

### `SetWantsStreamFormatsRestored`
```

--------------------------------

### GET GetStreamDirection

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiostream/getstreamdirection

Retrieves the direction of the audio stream, indicating whether it is an input or output stream.

```APIDOC
## GetStreamDirection

### Description
Gets the direction of the stream: input or output.

### Method
Instance Method

### Return Value
The direction of the stream, as a IOUserAudioStreamDirection value.
```

--------------------------------

### init (IOUserAudioObject)

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudioobject/init-1ar2z

Initializes an instance of the audio object base class using the provided IOUserAudioDriver.

```APIDOC
## init

### Description
Initializes an instance of the audio object base class. Always pass in the IOUserAudioDriver. The no-arg initializer, init, always returns false.

### Method
Initialization Method

### Parameters
#### Path Parameters
- **in_audio_driver** (IOUserAudioDriver) - Required - The IOUserAudioDriver that owns this object.

### Response
#### Success Response
- **Boolean** - Returns true if initialization succeeded, false otherwise.
```

--------------------------------

### IOUserAudioSliderControl - Accessing the Value

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudioslidercontrol

Details on how to set, get, and manage the value and range of an IOUserAudioSliderControl object.

```APIDOC
## Accessing the Value

### `SetControlValue`
Sets the value of the slider control.

### `GetControlValue`
Gets the value of the slider control.

### `SetRange`
Sets the range of possible values for the slider.

### `GetRange`
Gets the range of possible values for the slider.

### `IOUserAudioSliderRange`
A type that indicates minimum and maximum values for slider controls.
```

--------------------------------

### GetSupportsPrewarming Instance Method

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudioclockdevice/getsupportsprewarming

Call this method to determine if a clock device supports prewarming. A device supporting prewarming can enter a minimal state to be ready for immediate audio I/O on demand. This method synchronizes using the object's work queue.

```c++
bool GetSupportsPrewarming();
```

--------------------------------

### Initialize IOUserAudioControl Instance

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiocontrol/init

Use this method to initialize an instance of an audio control. Ensure DriverKit 21.0+ is available. The parameters specify the owning driver, settability, control element, and scope.

```c++
virtual bool init(IOUserAudioDriver *in_driver, bool in_is_settable, IOUserAudioObjectPropertyElement in_control_element, IOUserAudioObjectPropertyScope in_control_scope);
```

--------------------------------

### GET GetBaseClassID

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiostereopancontrol/getbaseclassid

Retrieves the audio class identifier of the base class object for an IOUserAudioStereoPanControl instance.

```APIDOC
## GetBaseClassID

### Description
Gets the audio class identifier of the base class object. This method overrides the base class IOUserAudioObject.

### Method
Virtual Method

### Return Value
- **IOUserAudioClassID** - The audio class identifier of the base class object.

### See Also
- GetClassID: Gets the audio class identifier of the object.
- IOUserAudioClassID: An identifier for the type of audio object.
```

--------------------------------

### GetDeviceIsAlive

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudioclockdevice/getdeviceisalive

Gets a Boolean value that represents whether the device is alive. Available in DriverKit 21.0+.

```APIDOC
## GetDeviceIsAlive

### Description
Gets a Boolean value that represents whether the device is alive.

### Method
Instance Method

### Endpoint
N/A (Instance Method)

### Parameters
None

### Request Body
None

### Response
#### Success Response
- **bool**: `true` if the device is alive; `false` otherwise.

### Response Example
```json
{
  "isAlive": true
}
```

### Discussion
This method synchronizes by using the work queue created by the object.
```

--------------------------------

### Implement NewUserClient_Impl for AudioDriverKit

Source: https://developer.apple.com/documentation/audiodriverkit/creating-an-audio-device-driver

Handles incoming user client connection requests by distinguishing between HAL requests and custom app connections.

```cpp
kern_return_t SimpleAudioDriver::NewUserClient_Impl(uint32_t in_type, IOUserClient** out_user_client)
{
	kern_return_t error = kIOReturnSuccess;
	
	// Have the superclass create the IOUserAudioDriverUserClient object
	// if the type is kIOUserAudioDriverUserClientType.
	if (in_type == kIOUserAudioDriverUserClientType)
	{
		error = super::NewUserClient(in_type, out_user_client, SUPERDISPATCH);
		FailIfError(error, , Failure, "Failed to create user client");
		FailIfNULL(*out_user_client, error = kIOReturnNoMemory, Failure, "Failed to create user client");
	}
	else
	{
		IOService* user_client_service = nullptr;
		error = Create(this, "SimpleAudioDriverUserClientProperties", &user_client_service);
		FailIfError(error, , Failure, "failed to create the SimpleAudioDriver user client");
		*out_user_client = OSDynamicCast(IOUserClient, user_client_service);
	}
	
Failure:
	return error;
}
```

--------------------------------

### GetDeviceIsRunning

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudioclockdevice/getdeviceisrunning

Gets a Boolean value that indicates whether the device is running. Available in DriverKit 21.0+.

```APIDOC
## GetDeviceIsRunning

### Description
Gets a Boolean value that indicates whether the device is running.

### Method
Instance Method

### Endpoint
N/A (Instance Method)

### Parameters
None

### Request Example
```c
bool GetDeviceIsRunning();
```

### Response
#### Success Response
- **bool**: `true` if the device is running; `false` otherwise.

### Response Example
```json
{
  "isRunning": true
}
```

### Discussion
This method synchronizes by using the work queue created by the object.
```

--------------------------------

### init (IOUserAudioBooleanControl)

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiobooleancontrol/init

Initializes an instance of a Boolean control for an audio driver.

```APIDOC
## init

### Description
Initializes an instance of a Boolean control.

### Parameters
- **in_driver** (IOUserAudioDriver) - Required - The IOUserAudioDriver that owns this object.
- **in_is_settable** (bool) - Required - A Boolean value that indicates if the control can be set.
- **in_control_value** (bool) - Required - A Boolean value that represents the control’s current value.
- **in_control_element** (IOUserAudioObjectPropertyElement) - Required - An IOUserAudioObjectPropertyElement to identify the control.
- **in_control_scope** (IOUserAudioObjectPropertyScope) - Required - A IOUserAudioObjectPropertyScope indicating the control’s scope: input, output, global, or play-through.
- **in_control_class_id** (IOUserAudioClassID) - Required - The IOUserAudioClassID of the control.

### Return Value
- **bool** - true if initialization succeeded; false otherwise.
```

--------------------------------

### Create an IOUserAudioStereoPanControl instance

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiostereopancontrol/create

Use this static method to allocate and initialize a new stereo pan control. Do not use this method if you are subclassing IOUserAudioStereoPanControl.

```cpp
static OSSharedPtr<IOUserAudioStereoPanControl> Create(IOUserAudioDriver *in_driver, bool in_is_settable, float in_control_value, IOUserAudioObjectPropertyElement in_left_channel, IOUserAudioObjectPropertyElement in_right_channel, IOUserAudioObjectPropertyElement in_control_element, IOUserAudioObjectPropertyScope in_control_scope, IOUserAudioClassID in_control_class_id);
```

--------------------------------

### Initialize an IOUserAudioClockDevice instance

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudioclockdevice/init

Use this method to initialize the audio clock device. It requires an IOUserAudioDriver instance and various OSString identifiers.

```cpp
virtual bool init(IOUserAudioDriver *in_driver, bool in_supports_prewarming, OSString *in_device_uid, OSString *in_model_uid, OSString *in_manufacturer_uid, uint32_t in_zero_timestamp_period);
```

--------------------------------

### Create IOUserAudioCustomProperty instance

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiocustomproperty/create

Allocates and initializes a new custom property object. Do not use this method if you are subclassing IOUserAudioCustomProperty.

```cpp
static OSSharedPtr<IOUserAudioCustomProperty> Create(IOUserAudioDriver *in_audio_driver, IOUserAudioObjectPropertyAddress in_prop_addr, bool in_is_property_settable, IOUserAudioCustomPropertyDataType in_qualifier_data_type, IOUserAudioCustomPropertyDataType in_data_type);
```

--------------------------------

### Slider Control Methods

Source: https://developer.apple.com/documentation/audiodriverkit/iouseraudiosliderrange

Methods for interacting with slider controls, including setting and getting values and ranges.

```APIDOC
## Slider Control Methods

### SetControlValue
Sets the value of the slider control.

### GetControlValue
Gets the value of the slider control.

### SetRange
Sets the range of possible values for the slider.

### GetRange
Gets the range of possible values for the slider.
```