IMMDeviceEnumerator::EnumAudioEndpoints method (mmdeviceapi.h)

Article
02/22/2024

The EnumAudioEndpoints method generates a collection of audio endpoint devices that meet the specified criteria.

Syntax

HRESULT EnumAudioEndpoints(
  [in]  EDataFlow           dataFlow,
  [in]  DWORD               dwStateMask,
  [out] IMMDeviceCollection **ppDevices
);

Parameters

[in] dataFlow

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.

[in] dwStateMask

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 DEVICE_STATE_XXX constants:

DEVICE_STATE_ACTIVE

DEVICE_STATE_DISABLED

DEVICE_STATE_NOTPRESENT

DEVICE_STATE_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.

[out] ppDevices

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.

Return value

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.

Remarks

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.

Examples

For a code example that calls the EnumAudioEndpoints method, see Device Properties.

Requirements

Requirement	Value
Minimum supported client	Windows Vista [desktop apps only]
Minimum supported server	Windows Server 2008 [desktop apps only]
Target Platform	Windows
Header	mmdeviceapi.h

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