> ## Documentation Index
> Fetch the complete documentation index at: https://devdocs.xbox.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Método IAudioStateMonitor::UnregisterCallback

> Método IAudioStateMonitor::UnregisterCallback

# Método IAudioStateMonitor::UnregisterCallback

Cancela o registro de um retorno de chamada registrado anteriormente com [IAudioStateMonitor::RegisterCallback](/pt-BR/reference/audio/audiostatemonitor/interfaces/iaudiostatemonitor-registercallback).

## Sintaxe

```cpp theme={null}
void UnregisterCallback(
  AudioStateMonitorRegistrationHandle registration
);
```

### Parâmetros

*registration*<br />Tipo: AudioStateMonitorRegistrationHandle

Um inteiro de 64 bits que identifica o retorno de chamada cujo registro será cancelado. Esse valor é retornado no parâmetro *registration* do método **RegisterCallback**.

### Valor de retorno

Este método não retorna um valor.

## Comentários

Considere o cenário a seguir, em que um jogo opta por reproduzir áudio GameMedia somente quando se sabe que o áudio não será silenciado pelo sistema operacional devido a uma política. Para conseguir isso, o jogo se registra para receber notificações de SoundLevel para a categoria de fluxo [AudioCategory\_GameMedia](https://learn.microsoft.com/windows/desktop/api/audiosessiontypes/ne-audiosessiontypes-audio_stream_category) no ponto de extremidade de console padrão. Se o SoundLevel dessa categoria estiver definido como 'Muted', o jogo interromperá a reprodução do fluxo GameMedia. Se o SoundLevel estiver definido como qualquer outro valor, o jogo optará por reproduzir o fluxo GameMedia.

```cpp theme={null}
// global variables 
winrt::com_ptr<IAudioStateMonitor> g_audioStateMonitor; 
AudioStateMonitorRegistrationHandle g_registration = 0; 

// Returns true if the GameMedia stream should be disabled, false if it should be 
// enabled. 
bool IsSoundLevelMuted(_In_ IAudioStateMonitor* audioStateMonitor) 
{ 
return (audioStateMonitor->GetSoundLevel() == AudioStateMonitorSoundLevel::Muted); 
} 

HRESULT StartTrackingSoundLevel() 
{ 
// Create an AudioStateMonitor and register for callbacks from it. 
HRESULT hr = RegisterForSoundLevelChanges(); 
if (SUCCEEDED(hr)) 
{ 
// Check the current sound level and determine if the GameMedia stream should 
// be enabled. 
bool disableGameMediaStream = IsSoundLevelMuted(g_audioStateMonitor.get()); 

// Add code here that enables or disables the GameMedia stream based on the 
// value of the boolean. 
} 
return hr; 
} 

HRESULT RegisterForSoundLevelChanges() 
{ 
HRESULT hr = S_OK; 

// Create a new AudioStateMonitor for the GameMedia category, if needed, and 
// register for callbacks. 
if (m_audioStateMonitor == nullptr) 
{ 
hr = CreateRenderAudioStateMonitorForCategoryAndDeviceRole( 
AudioCategory_GameMedia, ERole::eConsole, g_audioStateMonitor.put()); 
if (SUCCEEDED(hr)) 
{ 
// Optional "context" parameter is not used in this example, 
// and is set to nullptr. 
hr = g_audioStateMonitor->RegisterCallback(OnAudioStateMonitorCallback, nullptr, &g_registration); 
} 
} 

if (FAILED(hr)) 
{ 
// g_audioStateMonitor is a smart pointer, so if an IAudioStateMonitor was 
// allocated, setting the smart pointer to null invokes the Release method 
// which will decrement its usage count and ensure that the object is properly 
// destroyed. 
g_audioStateMonitor = nullptr; 
} 
return hr; 
} 

// Unregister callbacks on program shutdown 
void UnregisterForSoundLevelChanges() 
{ 
if (g_audioStateMonitor != nullptr) 
{ 
if (g_registration) 
{ 
g_audioStateMonitor->UnregisterCallback(g_registration); 
} 

// g_audioStateMonitor is a smart pointer, so setting it to null 
// invokes the Release method to decrement its usage count. 
g_audioStateMonitor = nullptr; 
} 
} 

void OnAudioStateMonitorCallback(_In_ IAudioStateMonitor* audioStateMonitor, _In_opt_ void* context) 
{ bool disableGameMediaStream = IsSoundLevelMuted(audioStateMonitor); 

// Add code here that enables or disables the GameMedia stream based on the value 
// of the boolean. 
} 
```

## Requisitos

**Cabeçalho:** Audiostatemonitorapi.h

**Plataformas compatíveis:** Windows, consoles da família XBOX One e consoles XBOX Series

## Confira também

[IAudioStateMonitor](/pt-BR/reference/audio/audiostatemonitor/interfaces/iaudiostatemonitor)

[Sobre o WASAPI](https://learn.microsoft.com/en-us/windows/desktop/CoreAudio/wasapi)


## Related topics

- [Método IAudioStateMonitor::UnregisterCallback](/es/reference/audio/audiostatemonitor/interfaces/iaudiostatemonitor-unregistercallback.md)
- [IAudioStateMonitor::UnregisterCallback method](/reference/audio/audiostatemonitor/interfaces/iaudiostatemonitor-unregistercallback.md)
- [IAudioStateMonitor::UnregisterCallback 方法](/zh-CN/reference/audio/audiostatemonitor/interfaces/iaudiostatemonitor-unregistercallback.md)
- [IAudioStateMonitor::UnregisterCallback メソッド](/ja-jp/reference/audio/audiostatemonitor/interfaces/iaudiostatemonitor-unregistercallback.md)
- [Método IAudioStateMonitor::RegisterCallback](/es/reference/audio/audiostatemonitor/interfaces/iaudiostatemonitor-registercallback.md)