Expressions

Most expression operators require (complete) object types. The only three exceptions are the unary & operator, the first operand of the comma operator, and the second and third operands of the ``?:'' operator. Most operators that accept pointer operands also permit pointers to incomplete types, unless pointer arithmetic is required. The list includes the unary ``'' operator, even though some may find this surprising. For example, given:

   void p

&p