phoneSetGain function (tapi.h)

The phoneSetGain function sets the gain of the microphone of the specified hookswitch device to the specified gain level.

Syntax

LONG phoneSetGain(
  HPHONE hPhone,
  DWORD  dwHookSwitchDev,
  DWORD  dwGain
);

Parameters

hPhone

Handle to the open phone device. The application must be the owner of the phone.

dwHookSwitchDev

Hookswitch device whose microphone's gain is to be set. This parameter uses one and only one of the PHONEHOOKSWITCHDEV_ Constants.

dwGain

Pointer to a DWORD containing the new gain setting of the device. The dwGain parameter specifies the gain 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. A value for dwGain that is out of range is set to the nearest value in the range.

Return value

Returns a positive request identifier if the function is completed asynchronously or a negative error number if an error occurs. The dwParam2 parameter of the corresponding PHONE_REPLY message is zero if the function succeeds or it is a negative error number if an error occurs. Possible return values are:

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

Requirements

See also

PHONE_REPLY

Supplementary Phone Service Functions

TAPI 2.2 Reference Overview