Command GetErrorStatus :

Execute command err? and return error code. 0 if not error.

GetErrorStatus Definition
Input Argument	Tango::DEV_VOID
Output Argument	Tango::DEV_LONG	Error code.
DisplayLevel	OPERATOR	..
Inherited	false	..
Abstract	false	..
Polling Period	Not polled	..
Command allowed for	All states	..