Returns the number of active worksheets
[C++]
static int InfoNumFile(
   long& lnumfile
);
A reference to a value that will contain the requested data if the macro succeeds.
Zero if the function has been called successfully; non-zero
            if the function could not be called.
            See Error codes for a list
            of return values.
See the Microsoft Excel on-line Help for full details about
            this function.
Header: xlfuncs.h