phoneGetGain function (tapi.h)

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

Syntax

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

Parameters

hPhone

Handle to the open phone device.

dwHookSwitchDev

Hookswitch device whose gain level is queried. The dwHookSwitchDev parameter can have only one bit set. This parameter uses one and only one of the PHONEHOOKSWITCHDEV_ Constants.

lpdwGain

Pointer to a DWORD 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 value

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.

Requirements

   
Target Platform Windows
Header tapi.h
Library Tapi32.lib
DLL Tapi32.dll

See also

Supplementary Phone Service Functions

TAPI 2.2 Reference Overview