The following restrictions apply to operator overloading:

1. Invention of new operators is not allowed. For example:

 void operator @ (int) ; //illegal, @ is not a built-in operator or a type name

2. Neither the precedence nor the number of arguments of an operator may be altered. An overloaded && for example, must have exactly two arguments–just like the built-in && operator.

3. The following operators cannot be overloaded:

 Direct member access operator 				. De-reference pointer to class member operator 		.*Scope resolution operator				::Conditional operator					?:Sizeof operator						sizeof

Similarly, any of the new casting operators: static_cast<>, dynamic_cast<>, reinterpret_cast<> and const_cast<>, as well as the # and ## preprocessor tokens, may not be overloaded.