WINSHELLAPI UINT APIENTRY SHAppBarMessage(
DWORD dwMessage,
PAPPBARDATA pData
);

Parameters
ABM_ACTIVATENotifies the system that an appbar has been activated.
ABM_GETAUTOHIDEBARRetrieves the handle of the autohide appbar associated with a particular edge of the screen.
ABM_GETSTATERetrieves the autohide and always-on-top states of the Windows taskbar.
ABM_GETTASKBARPOSRetrieves the bounding rectangle of the Windows taskbar.
ABM_NEWRegisters a new appbar and specifies the message identifier that the system should use to send notification messages to the appbar.
ABM_QUERYPOSRequests a size and screen position for an appbar.
ABM_REMOVEUnregisters an appbar, removing bar from the system's internal list.
ABM_SETAUTOHIDEBARRegisters or unregisters an autohide appbar for an edge of the screen.
ABM_SETPOSSets the size and screen position of an appbar.
ABM_WINDOWPOSCHANGEDNotifies the system when an appbar's position has changed.