Type support (basic types, RTTI)

See also type system overview and fundamental types defined by the language .

Additional basic types and macros

Defined in header <cstddef>
size_t	unsigned integer type returned by the sizeof operator (typedef)
ptrdiff_t	signed integer type returned when subtracting two pointers (typedef)
nullptr_t (C++11)	the type of the null pointer literal nullptr (typedef)
NULL	implementation-defined null pointer constant (macro constant)
max_align_t (C++11)	trivial type with alignment requirement as great as any other scalar type (typedef)
offsetof	byte offset from the beginning of a standard-layout type to specified member (function macro)
byte (C++17)	the byte type (enum)

Defined in header <cstdbool> (deprecated) (until C++20)
Defined in header <stdbool.h>
__bool_true_false_are_defined (C++11) (deprecated)	C compatibility macro constant, expands to integer literal 1 (macro constant)
Defined in header <cstdalign> (deprecated) (until C++20)
Defined in header <stdalign.h>
__alignas_is_defined (C++11) (deprecated)	C compatibility macro constant, expands to integer literal 1 (macro constant)
__alignof_is_defined (C++11) (deprecated)	C compatibility macro constant, expands to integer literal 1 (macro constant)

Fixed width integer types (since C++11)

Fixed width floating-point types (since C++23)

Numeric limits

Defined in header <limits>
numeric_limits	provides an interface to query properties of all fundamental numeric types (class template)

C numeric limits interface

Runtime type identification

Defined in header <typeinfo>
type_info	contains some type’s information, the class returned by the typeid operator (class)
bad_typeid	exception that is thrown if an argument in a typeid expression is null (class)
bad_cast	exception that is thrown by an invalid dynamic_cast expression, i.e. a cast of reference type fails (class)
Defined in header <typeindex>
type_index (C++11)	wrapper around a type_info object, that can be used as index in associative and unordered associative containers (class)

Defect reports

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

DR	Applied to	Behavior as published	Correct behavior
LWG 4036	C++11	__alignof_is_defined was underspecified in the C++ standard	specified and deprecated

See also

Type traits and metaprogramming library

C documentation for Type support library