3.9.1 Fundamental types
6 Values of type bool are either true or false.*42) [Note: there are no signed, unsigned, short, or long bool types or values. ] As described below, bool values behave as integral types. Values of type bool participate in integral promotions (4.5).
*42) Using a bool value in ways described by this International Standard as ‘‘undefined,’’ such as by examining the value of an uninitialized automatic variable, might cause it to behave as if is neither true nor false.
4.5 Integral promotions
4 An rvalue of type bool can be converted to an rvalue of type int, with false becoming zero and true becoming one.
5 These conversions are called integral promotions.