The EnumAudioEndpoints method generates a collection of audio endpoint devices that meet the specified criteria.
public:
HRESULT EnumAudioEndpoints(
EDataFlow dataFlow,
DWORD dwStateMask,
IMMDeviceCollection **ppDevices
)
dataFlow
Type: EDataFlow
[in]
The data-flow direction for the endpoint devices in the collection. The caller should set this parameter to one of the following EDataFlow enumeration values:
eRender
eCapture
eAll
If the caller specifies eAll, the method includes both rendering and capture endpoints in the collection.
dwStateMask
Type: DWORD
[in]
The state or states of the endpoints that are to be included in the collection. The caller should set this parameter to the bitwise OR of one or more of the following constants.
| Constant | Value | Description |
|---|---|---|
| DEVICE_STATE_ACTIVE | 0x00000001 | The audio endpoint device is active. That is, the audio adapter that connects to the endpoint device is present and enabled. In addition, if the endpoint device plugs into a jack on the adapter, then the endpoint device is plugged in. |
| DEVICE_STATE_DISABLED | 0x00000002 | The audio endpoint device is disabled. The user has disabled the device in the Windows multimedia control panel, Mmsys.cpl. |
| DEVICE_STATE_NOTPRESENT | 0x00000004 | The audio endpoint device is not present because the audio adapter that connects to the endpoint device has been removed from the system, or the user has disabled the adapter device in Device Manager. |
| DEVICE_STATE_UNPLUGGED | 0x00000008 | The audio endpoint device is unplugged. The audio adapter that contains the jack for the endpoint device is present and enabled, but the endpoint device is not plugged into the jack. Only a device with jack-presence detection can be in this state. |
| DEVICE_STATEMASK_ALL | 0x0000000F | Includes audio endpoint devices in all states—active, disabled, not present, and unplugged. |
For example, if the caller sets the dwStateMask parameter to DEVICE_STATE_ACTIVE | DEVICE_STATE_UNPLUGGED, the method includes endpoints that are either active or unplugged from their jacks, but excludes endpoints that are on audio adapters that have been disabled or are not present. To include all endpoints, regardless of state, set dwStateMask = DEVICE_STATEMASK_ALL.
ppDevices
Type: IMMDeviceCollection **
[out]
Pointer to a pointer variable into which the method writes the address of the IMMDeviceCollection interface of the device-collection object. Through this method, the caller obtains a counted reference to the interface. The caller is responsible for releasing the interface, when it is no longer needed, by calling the interface’s Release method. If the EnumAudioEndpoints call fails, ppDevices* is **NULL.
Type: HRESULT
If the method succeeds, it returns S_OK. If it fails, possible return codes include, but are not limited to, the values shown in the following table.
| Return code | Description |
|---|---|
| E_POINTER | Parameter ppDevices is NULL. |
| E_INVALIDARG | Parameter dataFlow or dwStateMask is out of range. |
| E_OUTOFMEMORY | Out of memory. |
Refer to WASAPI error codes.
For example, the following call enumerates all audio-rendering endpoint devices that are currently active (present and not disabled):
hr = pDevEnum->EnumAudioEndpoints(
eRender, DEVICE_STATE_ACTIVE,
&pEndpoints);
In the preceding code fragment, variable hr is of type HRESULT, pDevEnum is a pointer to an IMMDeviceEnumerator interface, and pEndpoints is a pointer to an IMMDeviceCollection interface.
Header: Declared in mmdeviceapi.h.
Library: Use MMDevApi.lib.