header

<type_traits>

type_traits

This header defines a series of classes to obtain type information on compile-time.

The header contains:

Helper classes: Standard classes to assist in creating compile-time constants.
Type traits: Classes to obtain characteristics of types in the form of compile-time constant values.
Type transformations: Classes to obtain new types by applying specific transformations to existing types.

A basic trait for types is the categories in which they can be classified. This is a chart on how these categories overlap:

	primary categories	composite categories
fundamental	void
	`std::nullptr_t`		scalar	object
	integral	arithmetic
	floating point	arithmetic
compound	pointer
	member object pointer	member pointer
	member function pointer	member pointer
	enum
	union
	class*
	array
	l-value reference	reference
	r-value reference	reference
	function

* = excluding unions

Helper classes

integral_constant: Integral constant (class template )

true_type: True type (class )

false_type: False type (class )

Type traits

Primary type categories

is_array: Is array (class template )

is_class: Is non-union class (class template )

is_enum: Is enum (class template )

is_floating_point: Is floating point (class template )

is_function: Is function (class template )

is_integral: Is integral (class template )

is_lvalue_reference: Is lvalue reference (class template )

is_member_function_pointer: Is member function pointer (class template )

is_member_object_pointer: Is member object pointer (class template )

is_pointer: Is pointer (class template )

is_rvalue_reference: Is rvalue reference (class template )

is_union: Is union (class template )

is_void: Is void (class template )

Composite type categories

is_arithmetic: Is arithmetic type (class template )

is_compound: Is compound type (class template )

is_fundamental: Is fundamental type (class template )

is_member_pointer: Is member pointer type (class template )

is_object: Is object type (class template )

is_reference: Is reference type (class template )

is_scalar: Is scalar type (class template )

Type properties

is_abstract: Is abstract class (class template )

is_const: Is const-qualified (class template )

is_empty: Is empty class (class template )

is_literal_type: Is literal type (class template )

is_pod: Is POD type (class template )

is_polymorphic: Is polymorphic (class template )

is_signed: Is signed type (class template )

is_standard_layout: Is standard-layout type (class template )

is_trivial: Is trivial type (class template )

is_trivially_copyable: Is trivially copyable (class template )

is_unsigned: Is unsigned type (class template )

is_volatile: Is volatile-qualified (class template )

Type features

has_virtual_destructor: Has virtual destructor (class template )

is_assignable: Is assignable (class template )

is_constructible: Is constructible (class template )

is_copy_assignable: Is copy assignable (class template )

is_copy_constructible: Is copy constructible (class template )

is_destructible: Is destructible (class template )

is_default_constructible: Is default constructible (class template )

is_move_assignable: Is move assignable (class template )

is_move_constructible: Is move constructible (class template )

is_trivially_assignable: Is trivially assignable (class template )

is_trivially_constructible: Is trivially constructible (class template )

is_trivially_copy_assignable: Is trivially copy assignable (class template )

is_trivially_copy_constructible: Is trivially copy constructible (class template )

is_trivially_destructible: Is trivially destructible (class template )

is_trivially_default_constructible: Is trivially default constructible (class template )

is_trivially_move_assignable: Is trivially move assignable (class template )

is_trivially_move_constructible: Is trivially move constructible (class template )

is_nothrow_assignable: Is assignable throwing no exceptions (class template )

is_nothrow_constructible: Is constructible throwing no exceptions (class template )

is_nothrow_copy_assignable: Is copy assignable throwing no exceptions (class template )

is_nothrow_copy_constructible: Is copy constructible throwing no exceptions (class template )

is_nothrow_destructible: Is nothrow destructible (class template )

is_nothrow_default_constructible: Is default constructible throwing no exceptions (class template )

is_nothrow_move_assignable: Is move assignable throwing no exception (class template )

is_nothrow_move_constructible: Is move constructible throwing no exceptions (class template )

Type relationships

is_base_of: Is base class of (class template )

is_convertible: Is convertible (class template )

is_same: Is same type (class template )

Property queries

alignment_of: Alignment of (class template )

extent: Array dimension extent (class template )

rank: Array rank (class template )

Type transformations

Const-volatile qualifications

add_const: Add const qualification (class template )

add_cv: Add const volatile qualification (class template )

add_volatile: Add volatile qualification (class template )

remove_const: Remove const qualification (class template )

remove_cv: Remove cv qualification (class template )

remove_volatile: Remove volatile qualification (class template )

Compound type alterations

add_pointer: Add pointer (class template )

add_lvalue_reference: Add lvalue reference (class template )

add_rvalue_reference: Add rvalue reference (class template )

decay: Decay type (class template )

make_signed: Make signed (class template )

make_unsigned: Make unsigned (class template )

remove_all_extents: Remove all array extents (class template )

remove_extent: Remove array extent (class template )

remove_pointer: Remove pointer (class template )

remove_reference: Remove reference (class template )

underlying_type: Underlying type of enum (class template )

Other type generators

aligned_storage: Aligned storage (class template )

aligned_union: Aligned union (class template )

common_type: Common type (class template )

conditional: Conditional type (class template )

enable_if: Enable type if condition is met (class template )

result_of: Result of call (class template )

<type_traits>

Helper classes

Type traits

Primary type categories

Composite type categories

Type properties

Type features

Type relationships

Property queries

Type transformations

Const-volatile qualifications

Compound type alterations

Other type generators

C++

Reference

C library:

Containers:

Input/Output:

Multi-threading:

Other:

<type_traits>

helper classes:

type traits:

type transformations: