Adds or removes an add-in from the working set
[C++]
static int AddinManager(
   unsigned short operation_num,
   const char* addinname_text,
   bool copy_logical = false
);
Operation_num determines the operation that the add-in manager will perform.
Addinname_text specifies the name or file name of the add-in.
Copy_logical specifies whether the add-in should be copied to the library directory.
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