NOSUBTRACT

Message        <Context> "<expression2>" cannot be subtracted from
               "<expression1>".

Description    Because of their types, the two expressions cannot be
               used as the operands of the subtraction operator.
               Either both operands must be arithmetic type, or both
               operands must be pointers to qualified or unqualified
               versions of compatible object types, or the left
               operand must be a pointer type and the right operand
               must be an integral type.

User Action    Modify the subtraction to use valid types.