phoneGetGain

The phoneGetGain function returns the gain setting of the microphone of the specified phone's hookswitch device.

LONG phoneGetGain(
  HPHONE hPhone,          
  DWORD dwHookSwitchDev,  
  LPDWORD lpdwGain        
);
 

Parameters

hPhone

A handle to the open phone device.

dwHookSwitchDev

The hookswitch device whose gain level is queried. The dwHookSwitchDev parameter can have only one bit set. This parameter uses the following PHONEHOOKSWITCHDEV_ constants:

PHONEHOOKSWITCHDEV_HANDSET

The phone's handset.

PHONEHOOKSWITCHDEV_SPEAKER

The phone's speakerphone or adjunct.

PHONEHOOKSWITCHDEV_HEADSET

The phone's headset.

lpdwGain

A pointer to a DWORD-sized location containing the current gain setting of the hookswitch microphone component. The dwGain parameter specifies the volume level of the hookswitch device. This is a number in the range 0x00000000 (silence) to 0x0000FFFF (maximum volume). The actual granularity and quantization of gain settings in this range are service provider-specific.

Return Values

Returns zero if the request succeeds or a negative error number if an error occurs. Possible return values are:

PHONEERR_INVALPHONEHANDLE, PHONEERR_NOMEM, PHONEERR_INVALPOINTER, PHONEERR_RESOURCEUNAVAIL, PHONEERR_INVALPHONESTATE, PHONEERR_OPERATIONFAILED, PHONEERR_INVALHOOKSWITCHDEV, PHONEERR_UNINITIALIZED, PHONEERR_OPERATIONUNAVAIL.

QuickInfo

  Version: Use TAPI version 1.4 and later.
  Header: Declared in tapi.h.
  Import Library: Link with tapi32.lib.

See Also

TAPI Reference Overview, Supplementary Phone Services Functions