is-integer-like , is-signed-integer-like

template< class T >
constexpr bool /*is-integer-like*/ = /* see description */;

template< class T >
constexpr bool /*is-signed-integer-like*/ = /* see description */;

Integer-class type

A type T is an integer-class type if it is in a set of implementation-defined types that behave as integer types do, as defined below. An integer-class type is not necessarily a class type.

An integer-class type can represent \(\scriptsize 2^N \)2^N consecutive integers, where N, a positive integer, is called the width of the integer-class type.

An integer-class type is either signed or unsigned:

• A signed integer class type can represent all integers in [\(\scriptsize -2^{N-1} \)-2^N-1, \(\scriptsize 2^{N-1}-1 \)2^N-1-1], where N is greater than the width of every signed integral type.
• An unsigned integer class type can represent all integers in [\(\scriptsize 0 \)0, \(\scriptsize 2^N-1 \)2^N-1], where N is greater than the width of every unsigned integral type.

All integer-class types model regular and three_way_comparable<std::strong_ordering>.

A value-initialized object of integer-class type has value 0.

An expression E of integer-class type T is contextually convertible to bool as if by bool(E != T(0)).

Integer-like type

A type other than (possibly cv-qualified) bool is integer-like if it models integral or if it is an integer-class type.

• An integer-like type is signed-integer-like if it models signed_integral or if it is a signed-integer-class type.
• An integer-like type is unsigned-integer-like if it models unsigned_integral or if it is an unsigned-integer-class type.

Required behaviors

Expressions of integer-class type are explicitly convertible to any integer-like type, and implicitly convertible to any integer-class type of equal or greater width and the same signedness. Expressions of integral type are both implicitly and explicitly convertible to any integer-class type. Conversions between integral and integer-class types and between two integer-class types do not exit via an exception. The result of such a conversion is the unique value of the destination type that is congruent to the source modulo \(\scriptsize 2^N \)2^N, where N is the width of the destination type.

Let Int<T> denote the following type:

• If T is an integer-class type, Int<T> is a unique hypothetical extended integer type of the same signedness with the same width as T.
• If T is an integral type, let Int<T> is the same type as T.

Given the following types, values and operators:

The following expressions must be well-formed and have their specified result and effects if the specified conditions are satisfied:

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

See also