mixerGetLineInfo

The mixerGetLineInfo function retrieves information about a specific line of a mixer device.

MMRESULT mixerGetLineInfo(
  HMIXEROBJ hmxobj,  
  LPMIXERLINE pmxl,  
  DWORD fdwInfo      
);
 

Parameters

hmxobj

Handle of the mixer device object that controls the specific audio line.

pmxl

Address of a MIXERLINE structure. This structure is filled with information about the audio line for the mixer device. The cbStruct member must always be initialized to be the size, in bytes, of the MIXERLINE structure.

fdwInfo

Flags for retrieving information about an audio line. The following values are defined:

MIXER_GETLINEINFOF_COMPONENTTYPE

The pmxl parameter will receive information about the first audio line of the type specified in the dwComponentType member of the MIXERLINE structure. This flag is used to retrieve information about an audio line of a specific component type. Remaining structure members except cbStruct require no further initialization.

MIXER_GETLINEINFOF_DESTINATION

The pmxl parameter will receive information about the destination audio line specified by the dwDestination member of the MIXERLINE structure. This index ranges from zero to one less than the value in the cDestinations member of the MIXERCAPS structure. All remaining structure members except cbStruct require no further initialization.

MIXER_GETLINEINFOF_LINEID

The pmxl parameter will receive information about the audio line specified by the dwLineID member of the MIXERLINE structure. This is usually used to retrieve updated information about the state of an audio line. All remaining structure members except cbStruct require no further initialization.

MIXER_GETLINEINFOF_SOURCE

The pmxl parameter will receive information about the source audio line specified by the dwDestination and dwSource members of the MIXERLINE structure. The index specified by dwDestination ranges from zero to one less than the value in the cDestinations member of the MIXERCAPS structure. The index specified by dwSource ranges from zero to one less than the value in the cConnections member of the MIXERLINE structure returned for the audio line stored in the dwDestination member. All remaining structure members except cbStruct require no further initialization.

MIXER_GETLINEINFOF_TARGETTYPE

The pmxl parameter will receive information about the audio line that is for the dwType member of the Target structure, which is a member of the MIXERLINE structure. This flag is used to retrieve information about an audio line that handles the target type (for example, MIXERLINE_TARGETTYPE_WAVEOUT). An application must initialize the dwType, wMid, wPid, vDriverVersion and szPname members of the MIXERLINE structure before calling mixerGetLineInfo. All of these values can be retrieved from the device capabilities structures for all media devices. Remaining structure members except cbStruct require no further initialization.

MIXER_OBJECTF_AUX

The hmxobj parameter is an auxiliary device identifier in the range of zero to one less than the number of devices returned by the auxGetNumDevs function.

MIXER_OBJECTF_HMIDIIN

The hmxobj parameter is the handle of a MIDI input device. This handle must have been returned by the midiInOpen function.

MIXER_OBJECTF_HMIDIOUT

The hmxobj parameter is the handle of a MIDI output device. This handle must have been returned by the midiOutOpen function.

MIXER_OBJECTF_HMIXER

The hmxobj parameter is a mixer device handle returned by the mixerOpen function. This flag is optional.

MIXER_OBJECTF_HWAVEIN

The hmxobj parameter is a waveform-audio input handle returned by the waveInOpen function.

MIXER_OBJECTF_HWAVEOUT

The hmxobj parameter is a waveform-audio output handle returned by the waveOutOpen function.

MIXER_OBJECTF_MIDIIN

The hmxobj parameter is the identifier of a MIDI input device. This identifier must be in the range of zero to one less than the number of devices returned by the midiInGetNumDevs function.

MIXER_OBJECTF_MIDIOUT

The hmxobj parameter is the identifier of a MIDI output device. This identifier must be in the range of zero to one less than the number of devices returned by the midiOutGetNumDevs function.

MIXER_OBJECTF_MIXER

The hmxobj parameter is a mixer device identifier in the range of zero to one less than the number of devices returned by the mixerGetNumDevs function. This flag is optional.

MIXER_OBJECTF_WAVEIN

The hmxobj parameter is the identifier of a waveform-audio input device in the range of zero to one less than the number of devices returned by the waveInGetNumDevs function.

MIXER_OBJECTF_WAVEOUT

The hmxobj parameter is the identifier of a waveform-audio output device in the range of zero to one less than the number of devices returned by the waveOutGetNumDevs function.

Return Values

Returns MMSYSERR_NOERROR if successful or an error otherwise. Possible error values include the following:

QuickInfo

  Windows NT: Requires version 3.1 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Unsupported.
  Header: Declared in mmsystem.h.
  Import Library: Use winmm.lib.
  Unicode: Implemented as Unicode and ANSI versions on Windows NT.

See Also

Audio Mixers Overview, Audio Mixer Functions, MIXERLINE, MIXERCAPS, auxGetNumDevs, midiInOpen, midiOutOpen, mixerOpen, waveInOpen, waveOutOpen, midiInGetNumDevs, midiOutGetNumDevs, mixerGetNumDevs, waveInGetNumDevs, waveOutGetNumDevs