std::byte

 

C++

Language

Standard library headers

Concepts

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)

Filesystem library (C++17)

Technical Specifications

 

Utilities library

Type support (basic types, RTTI, type traits)

Dynamic memory management

Error handling

Program utilities

Variadic functions

Date and time

Function objects

initializer_list (C++11)

bitset

hash (C++11)

Relational operators

rel_ops::operator!=rel_ops::operator>rel_ops::operator<=rel_ops::operator>=

optional, any and variant (C++17)

optional

any

variant

in_placein_place_typein_place_indexin_place_tin_place_type_tin_place_index_t

Pairs and tuples

pair

tuple (C++11)

apply (C++17)

make_from_tuple (C++17)

piecewise_construct_t (C++11)

piecewise_construct (C++11)

integer_sequence (C++14)

Swap, forward and move

swap

exchange (C++14)

forward (C++11)

move (C++11)

move_if_noexcept (C++11)

Elementary string conversions

to_chars (C++17)

from_chars (C++17)

chars_format (C++17)

Type operations

declval (C++11)

as_const (C++17)

 

Type support

Basic types
Fundamental types
Fixed width integer types (C++11)
ptrdiff_t size_t max_align_t (C++11) byte (C++17)	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
Type categories
is_void (C++11) is_null_pointer (C++14) is_array (C++11) is_pointer (C++11) is_enum (C++11) is_union (C++11) is_class (C++11) is_function (C++11)	is_object (C++11) is_scalar (C++11) is_compound (C++11) is_integral (C++11) is_floating_point (C++11) is_fundamental (C++11) is_arithmetic (C++11)
is_reference (C++11)
is_lvalue_reference (C++11)
is_rvalue_reference (C++11)
is_member_pointer (C++11)
is_member_object_pointer (C++11)
is_member_function_pointer (C++11)

Type properties
is_const (C++11) is_volatile (C++11) is_pod (C++11) is_empty (C++11) is_polymorphic (C++11) is_final (C++14) is_abstract (C++11)	is_trivial (C++11) is_trivially_copyable (C++11) is_standard_layout (C++11) is_literal_type (C++11)(deprecated in C++17) is_aggregate (C++17) is_signed (C++11) is_unsigned (C++11)
has_unique_object_representations (C++17)
Type trait constants
integral_constantbool_constanttrue_typefalse_type (C++11)(C++17)(C++11)(C++11)
Metafunctions
conjunction (C++17)
disjunction (C++17)
negation (C++17)

Supported operations
is_constructibleis_trivially_constructibleis_nothrow_constructible (C++11)(C++11)(C++11)
is_default_constructibleis_trivially_default_constructibleis_nothrow_default_constructible (C++11)(C++11)(C++11)
is_copy_constructibleis_trivially_copy_constructibleis_nothrow_copy_constructible (C++11)(C++11)(C++11)
is_move_constructibleis_trivially_move_constructibleis_nothrow_move_constructible (C++11)(C++11)(C++11)
is_assignableis_trivially_assignableis_nothrow_assignable (C++11)(C++11)(C++11)
is_copy_assignableis_trivially_copy_assignableis_nothrow_copy_assignable (C++11)(C++11)(C++11)
is_move_assignableis_trivially_move_assignableis_nothrow_move_assignable (C++11)(C++11)(C++11)
is_destructibleis_trivially_destructibleis_nothrow_destructible (C++11)(C++11)(C++11)
has_virtual_destructor (C++11)
is_swappable_withis_swappableis_nothrow_swappable_withis_nothrow_swappable (C++17)(C++17)(C++17)(C++17)
Relationships and property queries
is_same (C++11) is_base_of (C++11) is_convertible (C++11)	alignment_of (C++11) rank (C++11) extent (C++11)
is_invocableis_invocable_ris_nothrow_invocableis_nothrow_invocable_r (C++17)(C++17)(C++17)(C++17)
Type modifications
remove_cvremove_constremove_volatile (C++11)(C++11)(C++11) add_cvadd_constadd_volatile (C++11)(C++11)(C++11) make_signed (C++11) make_unsigned (C++11)	remove_reference (C++11) add_lvalue_referenceadd_rvalue_reference (C++11)(C++11) remove_pointer (C++11) add_pointer (C++11) remove_extent (C++11) remove_all_extents (C++11)
Type transformations
aligned_storage (C++11) aligned_union (C++11) decay (C++11) enable_if (C++11) void_t (C++17)	conditional (C++11) common_type (C++11) underlying_type (C++11) result_ofinvoke_result (C++11)(deprecated in C++17)(C++17)

 

Defined in header <cstddef>
enum class byte : unsigned char {} ;		(since C++17)

std::byte is a distinct type that implements the concept of byte as specified in the C++ language definition.

Like the character types (char, unsigned char, signed char) it can be used to access raw memory occupied by other objects (object representation), but unlike those types, it is not a character type and is not an arithmetic type. A byte is only a collection of bits, and only bitwise logic operators are defined for it.

Non-member functions

std::to_integer

template <class IntegerType>  constexpr IntegerType to_integer(std::byte b) noexcept;		(since C++17)

Equivalent to: return IntegerType(b); This overload only participates in overload resolution if std::is_integral_v<IntegerType> is true.

std::operator<<=,operator>>=

template <class IntegerType>  constexpr std::byte& operator<<=(std::byte& b, IntegerType shift) noexcept;	(1)	(since C++17)
template <class IntegerType>  constexpr std::byte& operator>>=(std::byte& b, IntegerType shift) noexcept;	(2)	(since C++17)

1) Equivalent to: return b = std::byte(static_cast<unsigned char>(b) << shift); This overload only participates in overload resolution if std::is_integral_v<IntegerType> is true.

2) Equivalent to: return b = std::byte(static_cast<unsigned char>(b) >> shift);

This overload only participates in overload resolution if std::is_integral_v<IntegerType> is true.

std::operator<<,operator>>

template <class IntegerType>  constexpr std::byte operator <<(std::byte b, IntegerType shift) noexcept;	(1)	(since C++17)
template <class IntegerType>  constexpr std::byte operator >>(std::byte b, IntegerType shift) noexcept;	(2)	(since C++17)

1) Equivalent to: return std::byte(static_cast<unsigned char>(b) << shift); This overload only participates in overload resolution if std::is_integral_v<IntegerType> is true.

2) Equivalent to: return std::byte(static_cast<unsigned char>(b) >> shift);

This overload only participates in overload resolution if std::is_integral_v<IntegerType> is true.

std::operator|=,operator&=,operator^=

constexpr std::byte& operator|=(std::byte& l, std::byte r) noexcept;	(1)	(since C++17)
constexpr std::byte& operator&=(std::byte& l, std::byte r) noexcept;	(2)	(since C++17)
constexpr std::byte& operator^=(std::byte& l, std::byte r) noexcept;	(3)	(since C++17)

1) Equivalent to: return l = std::byte(static_cast<unsigned char>(l) | static_cast<unsigned char>(r));.

2) Equivalent to: return l = std::byte(static_cast<unsigned char>(l) & static_cast<unsigned char>(r));.

3) Equivalent to: return l = std::byte(static_cast<unsigned char>(l) ^ static_cast<unsigned char>(r));.

std::operator|,operator&,operator^,operator~

constexpr std::byte operator|(std::byte l, std::byte r) noexcept;	(1)	(since C++17)
constexpr std::byte operator&(std::byte l, std::byte r) noexcept;	(2)	(since C++17)
constexpr std::byte operator^(std::byte l, std::byte r) noexcept;	(3)	(since C++17)
constexpr std::byte operator~(std::byte b) noexcept;	(4)	(since C++17)

1) Equivalent to: return std::byte(static_cast<unsigned char>(l) | static_cast<unsigned char>(r));.

2) Equivalent to: return std::byte(static_cast<unsigned char>(l) & static_cast<unsigned char>(r));.

3) Equivalent to: return std::byte(static_cast<unsigned char>(l) ^ static_cast<unsigned char>(r));.

4) Equivalent to: return std::byte(~static_cast<unsigned char>(b));

Notes

A numeric value n can be converted to a byte value using std::byte{n} , due to C++17 relaxed enum class initialization rules.

A byte can be converted to a numeric value (such as to produce a integer hash of an object) using std::to_integer