Type support (basic types, RTTI, type traits)

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C++ Standard Library
Language Utilities library Strings library Containers library Algorithms library Iterators library Numerics library Input/output library Localizations library Regular expressions library (C++11) Atomic operations library (C++11) Thread support library (C++11)
Utilities library
Type support
Basic types Fundamental types Fixed width integer types (C++11) ptrdiff_t size_t max_align_t (C++11) nullptr_t (C++11) offsetof NULL Numeric limits numeric_limits C numeric limits interface Runtime type information type_info type_index (C++11) bad_typeid bad_cast Type traits (C++11) Type categories (C++11) is_void is_array is_pointer is_enum is_union is_class is_function is_object is_scalar is_compound is_integral is_floating_point is_reference is_lvalue_reference is_rvalue_reference is_member_pointer is_member_object_pointer is_member_function_pointer is_arithmetic is_fundamental Type properties (C++11) is_const is_volatile is_pod is_empty is_polymorphic is_abstract is_trivial is_trivially_copyable is_standard_layout is_literal_type is_signed is_unsigned Supported operations (C++11) is_constructible is_trivially_constructible is_nothrow_constructible is_default_constructible is_trivially_default_constructible is_nothrow_default_constructible is_copy_constructible is_trivially_copy_constructible is_nothrow_copy_constructible is_move_constructible is_trivially_move_constructible is_nothrow_move_constructible is_assignable is_trivially_assignable is_nothrow_assignable is_copy_assignable is_trivially_copy_assignable is_nothrow_copy_assignable is_move_assignable is_trivially_move_assignable is_nothrow_move_assignable is_destructible is_trivially_destructible is_nothrow_destructible has_virtual_destructor Relationships and property queries (C++11) is_same is_base_of is_convertible alignment_of rank extent Type modifications (C++11) remove_cv remove_const remove_volatile add_cv add_const add_volatile make_signed make_unsigned remove_reference add_lvalue_reference add_rvalue_reference remove_pointer add_pointer remove_extent remove_all_extents Type transformations (C++11) aligned_storage aligned_union decay enable_if conditional common_type underlying_type result_of Type trait constants (C++11) integral_constant

Contents 1 Basic types 1.1 Fundamental types defined by the language 1.2 Additional basic types and macros 1.3 Fixed width integer types (C++11 feature) 1.4 numeric_limits 1.5 C numeric limits interface 2 Runtime type identification 3 Type traits (C++11 feature) 3.1 Type properties 3.1.1 Primary type categories 3.1.2 Composite type categories 3.1.3 Type properties 3.1.4 Supported operations 3.1.5 Property queries 3.1.6 Type relationships 3.2 Type modifications 3.2.1 Const-volatility specifiers 3.2.2 References 3.2.3 Pointers 3.2.4 Sign modifiers 3.2.5 Arrays 3.3 Miscellaneous transformations 3.4 Helper classes

[edit] Basic types

[edit] Fundamental types defined by the language

[edit] 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)	POD 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)

[edit] Fixed width integer types (C++11 feature)

[edit] numeric_limits

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

[edit] C numeric limits interface

[edit] Runtime type identification

type_info	contains some type's information, generated by the implementation. This is the class, returned by the typeid operator (class)
type_index (C++11)	wrapper around a type_info object, that can be used as index in associative and unordered associative containers (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)

[edit] Type traits (C++11 feature)

Type traits defines an compile-time template-based interface to query or modify the properties of types.

[edit] Type properties

Defined in header <type_traits>
Primary type categories
is_void (C++11)	checks if a type is void (class template)
is_integral (C++11)	checks if a type is integral type (class template)
is_floating_point (C++11)	checks if a type is floating-point type (class template)
is_array (C++11)	checks if a type is an array type (class template)
is_pointer (C++11)	checks if a type is a pointer type (class template)
is_lvalue_reference (C++11)	checks if a type is lvalue reference (class template)
is_rvalue_reference (C++11)	checks if a type is rvalue reference (class template)
is_member_object_pointer (C++11)	checks if a type is a pointer to a non-static member object (class template)
is_member_function_pointer (C++11)	checks if a type is a pointer to a non-static member function (class template)
is_enum (C++11)	checks if a type is an enumeration type (class template)
is_union (C++11)	checks if a type is an union type (class template)
is_class (C++11)	checks if a type is a class type (but not union type) (class template)
is_function (C++11)	checks if a type is a function type (class template)
Composite type categories
is_reference (C++11)	checks if a type is either lvalue reference or rvalue reference (class template)
is_arithmetic (C++11)	checks if a type is arithmetic type (class template)
is_fundamental (C++11)	checks if a type is fundamental type (class template)
is_object (C++11)	checks if a type is object type (class template)
is_scalar (C++11)	checks if a type is scalar type (class template)
is_compound (C++11)	checks if a type is compound type (class template)
is_member_pointer (C++11)	checks if a type is a pointer to a non-static member function or object (class template)
Type properties
is_const (C++11)	checks if a type is const-qualified (class template)
is_volatile (C++11)	checks if a type is volatile-qualified (class template)
is_trivial (C++11)	checks if a type is trivial (class template)
is_trivially_copyable (C++11)	checks if a type is trivially copyable (class template)
is_standard_layout (C++11)	checks if a type is standard-layout type (class template)
is_pod (C++11)	checks if a type is plain-old data (POD) type (class template)
is_literal_type (C++11)	checks if a type is literal type (class template)
is_empty (C++11)	checks if a type is class (but not union) type and has no data (class template)
is_polymorphic (C++11)	checks if a type is polymorphic class type (class template)
is_abstract (C++11)	checks if a type is abstract class type (class template)
is_signed (C++11)	checks if a type is signed arithmetic type (class template)
is_unsigned (C++11)	checks if a type is unsigned arithmetic type (class template)

Supported operations
is_constructible is_trivially_constructible is_nothrow_constructible (C++11) (C++11) (C++11)	checks if a type has a constructor for specific arguments (class template)
is_default_constructible is_trivially_default_constructible is_nothrow_default_constructible (C++11) (C++11) (C++11)	checks if a type has a default constructor (class template)
is_copy_constructible is_trivially_copy_constructible is_nothrow_copy_constructible (C++11) (C++11) (C++11)	checks if a type has a copy constructor (class template)
is_move_constructible is_trivially_move_constructible is_nothrow_move_constructible (C++11) (C++11) (C++11)	checks if a type has a move constructor (class template)
is_assignable is_trivially_assignable is_nothrow_assignable (C++11) (C++11) (C++11)	checks if a type has a assignment operator for a specific argument (class template)
is_copy_assignable is_trivially_copy_assignable is_nothrow_copy_assignable (C++11) (C++11) (C++11)	checks if a type has a copy assignment operator (class template)
is_move_assignable is_trivially_move_assignable is_nothrow_move_assignable (C++11) (C++11) (C++11)	checks if a type has a move assignment operator (class template)
is_destructible is_trivially_destructible is_nothrow_destructible (C++11) (C++11) (C++11)	checks if a type has a non-deleted destructor (class template)
has_virtual_destructor (C++11)	checks if a type has a virtual destructor (class template)

Property queries
alignment_of (C++11)	obtains the type's alignment requirements (class template)
rank (C++11)	obtains the number of dimensions of an array type (class template)
extent (C++11)	obtains the size of an array type along a specified dimension (class template)

Type relationships
is_same (C++11)	checks if two types are the same (class template)
is_base_of (C++11)	checks if a type is derived from the other type (class template)
is_convertible (C++11)	checks if a type can be converted to the other type (class template)

[edit] Type modifications

Type modification templates create new type definitions by applying modifications on a template parameter. The resulting type can then be accessed through type member typedef.

Defined in header <type_traits>
Const-volatility specifiers
remove_cv remove_const remove_volatile (C++11) (C++11) (C++11)	removes const or/and volatile specifiers from the given type (class template)
add_cv add_const add_volatile (C++11) (C++11) (C++11)	adds const or/and volatile specifiers to the given type (class template)
References
remove_reference (C++11)	removes reference from the given type (class template)
add_lvalue_reference add_rvalue_reference (C++11) (C++11)	adds lvalue or rvalue reference to the given types (class template)
Pointers
remove_pointer (C++11)	removes pointer from the given type (class template)
add_pointer (C++11)	adds pointer to the given type (class template)
Sign modifiers
make_signed (C++11)	makes the given integral type signed (class template)
make_unsigned (C++11)	makes the given integral type unsigned (class template)
Arrays
remove_extent (C++11)	removes one extent from the given array type (class template)
remove_all_extents (C++11)	removes all extents from the given array type (class template)

[edit] Miscellaneous transformations

Defined in header <type_traits>
aligned_storage (C++11)	defines the type suitable for use as uninitialized storage for types of given size (class template)
aligned_union (C++11)	defines the type suitable for use as uninitialized storage for all given types (class template)
decay (C++11)	applies type transformations as when passing a function argument by value (class template)
enable_if (C++11)	hides a function overload or template specialization based on compile-time boolean (class template)
conditional (C++11)	chooses one type or another based on compile-type boolean (class template)
common_type (C++11)	deduces the result type of a mixed-mode arithmetic expression (class template)
underlying_type (C++11)	obtains the underlying integer type for a given enumeration type (class template)
result_of (C++11)	deduces the return type of a function call expresion (class template)

[edit] Helper classes

Defined in header <type_traits>
integral_constant (C++11)	compile-time constant of specified type with specified value (class template)

Two specializations of std::integral_constant for the type bool are provided:

Defined in header <type_traits>
Type	Definition
true_type	std::integral_constant<bool, true>
false_type	std::integral_constant<bool, false>