The phoneSetHookSwitch function sets the hook state of the specified open phone's hookswitch devices to the specified mode. Only the hookswitch state of the hookswitch devices listed is affected.
LONG phoneSetHookSwitch(
HPHONE hPhone,
DWORD dwHookSwitchDevs,
DWORD dwHookSwitchMode
);
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_OPERATIONUNAVAIL, PHONEERR_NOTOWNER, PHONEERR_NOMEM, PHONEERR_INVALHOOKSWITCHDEV, PHONEERR_RESOURCEUNAVAIL, PHONEERR_INVALHOOKSWITCHMODE, PHONEERR_OPERATIONFAILED, PHONEERR_INVALPHONESTATE, PHONEERR_UNINITIALIZED.
The hookswitch mode is the same for all specified devices. If different settings are desired, this function can be invoked multiple times with a different set of parameters. A PHONE_STATE message is sent to the application after the hookswitch state has changed.
Version: Use TAPI version 1.4 and later.
Header: Declared in tapi.h.
Import Library: Link with tapi32.lib.
TAPI Reference Overview, Supplementary Phone Services Functions, PHONE_REPLY, PHONE_STATE