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Reference

Synopsis

  • Before use, read the limitations of functionality.

  • To check is magic_enum supported compiler use macro MAGIC_ENUM_SUPPORTED or constexpr constant magic_enum::is_magic_enum_supported.
    If magic_enum used on unsupported compiler, occurs the compilation error. To suppress error define macro MAGIC_ENUM_NO_CHECK_SUPPORT.

  • To add custom enum or type names see the example.

  • To change the type of strings or ortional, use special macros:

    #include <my_lib/string.hpp>
    #include <my_lib/string_view.hpp>
    #define MAGIC_ENUM_USING_ALIAS_STRING using string = my_lib::String;
    #define MAGIC_ENUM_USING_ALIAS_STRING_VIEW using string_view = my_lib::StringView;
    #define MAGIC_ENUM_USING_ALIAS_OPTIONAL template <typename T> using optional = my_lib::Optional<T>;
    #include <magic_enum.hpp>
  • Optionally define MAGIC_ENUM_CONFIG_FILE i.e., in your build system, with path to header file with defined macros or constants, for example:

    #define MAGIC_ENUM_CONFIG_FILE "my_magic_enum_cfg.hpp"

    my_magic_enum_cfg.hpp:

    #include <my_lib/string.hpp>
    #include <my_lib/string_view.hpp>
    #define MAGIC_ENUM_USING_ALIAS_STRING using string = my_lib::String;
    #define MAGIC_ENUM_USING_ALIAS_STRING_VIEW using string_view = my_lib::StringView;
    #define MAGIC_ENUM_USING_ALIAS_OPTIONAL template <typename T> using optional = my_lib::Optional<T>;
    #define MAGIC_ENUM_RANGE_MIN 0
    #define MAGIC_ENUM_RANGE_MAX 255
  • To add support for non-ASCII enumeration identifier, use special macros:

    #define MAGIC_ENUM_ENABLE_NONASCII
    #include <magic_enum.hpp>

enum_cast

template <typename E>
constexpr optional<E> enum_cast(underlying_type_t<E> value) noexcept;

template <typename E>
constexpr optional<E> enum_cast(string_view value) noexcept;

template <typename E, typename BinaryPredicate>
constexpr optional<E> enum_cast(string_view value, BinaryPredicate p) noexcept(is_nothrow_invocable_v<BinaryPredicate>);
  • Obtains enum value from string or integer.

  • Returns optional<E>, using has_value() to check contains enum value and value() to get the enum value.

  • If argument does not enum value, returns empty optional.

  • Examples

    • String to enum value.

      string color_name{"GREEN"};
      auto color = magic_enum::enum_cast<Color>(color_name);
      if (color.has_value()) {
          // color.value() -> Color::GREEN
      }
      
      auto color_or_default = magic_enum::enum_cast<Color>(value).value_or(Color::NONE);
    • Integer to enum value.

      int color_integer = 2;
      auto color = magic_enum::enum_cast<Color>(color_integer);
      if (color.has_value()) {
          // color.value() -> Color::RED
      }
      
      auto color_or_default = magic_enum::enum_cast<Color>(value).value_or(Color::NONE);

enum_value

template <typename E>
constexpr E enum_value(size_t index) noexcept;

template <typename E, size_t I>
constexpr E enum_value() noexcept;
  • Returns enum value at specified index.

    • enum_value(value) no bounds checking is performed: the behavior is undefined if index >= number of enum values.
    • enum_value<value>() check if I >= number of enum values, occurs the compilation error magic_enum::enum_value out of range.
  • Examples

    int i = 1;
    Color color = magic_enum::enum_value<Color>(i);
    // color -> Color::BLUE
    Color color = magic_enum::enum_value<Color, 1>();
    // color -> Color::BLUE

enum_values

template <typename E>
constexpr array<E, N> enum_values() noexcept;
  • Returns array<E, N> with all enum values where N = number of enum values, sorted by enum value.

  • Examples

    constexpr auto colors = magic_enum::enum_values<Color>();
    // colors -> {Color::RED, Color::BLUE, Color::GREEN}
    // colors[0] -> Color::RED

enum_count

template <typename E>
constexpr size_t enum_count() noexcept;
  • Returns number of enum values.

  • Examples

    constexpr auto color_count = magic_enum::enum_count<Color>();
    // color_count -> 3

enum_integer

template <typename E>
constexpr underlying_type_t<E> enum_integer(E value) noexcept;

template <typename E>
constexpr underlying_type_t<E> enum_underlying(E value) noexcept;
  • Returns integer value from enum value.

  • Examples

    Color color = Color::RED;
    auto color_integer = magic_enum::enum_integer(color);
    // color -> 2

enum_name

template <typename E>
constexpr string_view enum_name(E value) noexcept;

template <auto V>
constexpr string_view enum_name() noexcept;
  • Returns name from enum value as string_view with null-terminated string.

    • If enum value does not have name or out of range, enum_name(value) returns empty string.
    • If enum value does not have name, enum_name<value>() occurs the compilation error magic_enum::enum_name enum value does not have a name.
  • enum_name<value>() is much lighter on the compile times and is not restricted to the enum_range limitation.

  • Examples

    Color color = Color::RED;
    auto color_name = magic_enum::enum_name(color);
    // color_name -> "RED"
    constexpr Color color = Color::BLUE;
    constexpr auto color_name = magic_enum::enum_name<color>();
    // color_name -> "BLUE"

enum_names

template <typename E>
constexpr array<string_view, N> enum_names() noexcept;
  • Returns array<string_view, N> with all names where N = number of enum values, sorted by enum value.

  • Examples

    constexpr auto color_names = magic_enum::enum_names<Color>();
    // color_names -> {"RED", "BLUE", "GREEN"}
    // color_names[0] -> "RED"

enum_entries

template <typename E>
constexpr array<pair<E, string_view>, N> enum_entries() noexcept;
  • Returns array<pair<E, string_view>, N> with all pairs (value, name) where N = number of enum values, sorted by enum value.

  • Examples

    constexpr auto color_entries = magic_enum::enum_entries<Color>();
    // color_entries -> {{Color::RED, "RED"}, {Color::BLUE, "BLUE"}, {Color::GREEN, "GREEN"}}
    // color_entries[0].first -> Color::RED
    // color_entries[0].second -> "RED"

enum_index

template <typename E>
constexpr optional<size_t> enum_index(E value) noexcept;

template <auto V>
constexpr size_t enum_index() noexcept;
  • Obtains index in enum values from enum value.

    • enum_index(value) returns optional<size_t> with index.
    • enum_index<value>() returns index. If enum value does not have a index, occurs the compilation error magic_enum::enum_index enum value does not have a index.
  • Examples

    constexpr auto color_index = magic_enum::enum_index(Color::BLUE);
    // color_index.value() -> 1
    // color_index.has_value() -> true
    constexpr auto color_index = magic_enum::enum_index<Color::BLUE>();
    // color_index -> 1

enum_contains

template <typename E>
constexpr bool enum_contains(E value) noexcept;

template <typename E>
constexpr bool enum_contains(underlying_type_t<E> value) noexcept;

template <typename E>
constexpr bool enum_contains(string_view value) noexcept;

template <typename E, typename BinaryPredicate>
constexpr optional<E> enum_contains(string_view value, BinaryPredicate p) noexcept(is_nothrow_invocable_v<BinaryPredicate>);
  • Checks whether enum contains enumerator with such value.

  • Returns true is enum contains value, otherwise false.

  • Examples

    magic_enum::enum_contains(Color::GREEN); // -> true
    magic_enum::enum_contains<Color>(2); // -> true
    magic_enum::enum_contains<Color>(123); // -> false
    magic_enum::enum_contains<Color>("GREEN"); // -> true
    magic_enum::enum_contains<Color>("fda"); // -> false

enum_type_name

template <typename E>
constexpr string_view enum_type_name() noexcept;
  • Returns type name of enum as string_view null-terminated string.

  • Examples

    Color color = Color::RED;
    auto type_name = magic_enum::enum_type_name<decltype(color)>();
    // type_name -> "Color"

enum_fuse

template <typename... Es>
[[nodiscard]] constexpr optional<enum_fuse_t> enum_fuse(Es... values) noexcept;
  • You should add the required file <magic_enum_fuse.hpp>.

  • Returns a typesafe bijective mix of several enum values. This can be used to emulate 2D switch/case statements.

  • Return type is optional<enum_fuse_t> where enum_fuse_t is an incomplete enum, it is unique for any given combination of Es....

  • Switch/case statement over an incomplete enum is a Visual Studio warning C4064

    • You have to silent (/wd4064) or ignore it.
    • Alternatively, define MAGIC_ENUM_NO_TYPESAFE_ENUM_FUSE to disable type-safety (enum_fuse_t equals uintmax_t).
  • Examples

    switch (magic_enum::enum_fuse(color, direction).value()) {
      case magic_enum::enum_fuse(Color::RED, Directions::Up).value(): // ...
      case magic_enum::enum_fuse(Color::BLUE, Directions::Down).value(): // ...
      case magic_enum::enum_fuse(Directions::BLUE, Color::Down).value(): // Compilation error
    // ...
    }

enum_switch

template <typename Result = void, typename E, typename Lambda>
constexpr Result enum_switch(Lambda&& lambda, E value);

template <typename Result, typename E, typename Lambda>
constexpr Result enum_switch(Lambda&& lambda, E value, Result&& result);
  • You should add the required file <magic_enum_switch.hpp>.

  • Examples

    Color color = Color::RED;
    
    magic_enum::enum_switch([] (auto val) {
      constexpr Color c_color = val;
      // ...
    }, color);

enum_for_each

template <typename E, typename Lambda>
constexpr auto enum_for_each(Lambda&& lambda);
  • Examples

    magic_enum::enum_for_each<Color>([] (auto val) {
      constexpr Color c_color = val;
      // ...
    });

enum_flags

template <typename E>
string enum_flags_name(E value);

template <typename E>
constexpr optional<E> enum_flags_cast(underlying_type_t<E> value) noexcept;

template <typename E>
constexpr optional<E> enum_flags_cast(string_view value) noexcept;

template <typename E, typename BinaryPredicate>
constexpr optional<E> enum_flags_cast(string_view value, BinaryPredicate p) noexcept(is_nothrow_invocable_v<BinaryPredicate>);

template <typename E>
constexpr bool enum_flags_contains(E value) noexcept;

template <typename E>
constexpr bool enum_flags_contains(underlying_type_t<E> value) noexcept;

template <typename E>
constexpr bool enum_flags_contains(string_view value) noexcept;

template <typename E, typename BinaryPredicate>
constexpr optional<E> enum_flags_contains(string_view value, BinaryPredicate p) noexcept(is_nothrow_invocable_v<BinaryPredicate>);
  • Examples

    auto directions_name = magic_enum::enum_flags_name(Directions::Up | Directions::Right);
    // directions_name -> "Directions::Up|Directions::Right"

is_unscoped_enum

template <typename T>
struct is_unscoped_enum;

template <typename T>
inline constexpr bool is_unscoped_enum_v = is_unscoped_enum<T>::value;
  • Checks whether type is an Unscoped enumeration.

  • Provides the member constant value which is equal to true, if T is an Unscoped enumeration type.
    Otherwise, value is equal to false.

  • Examples

    magic_enum::is_unscoped_enum<color>::value -> true
    magic_enum::is_unscoped_enum<Direction>::value -> false
    
    // Helper variable template.
    magic_enum::is_unscoped_enum_v<color> -> true

is_scoped_enum

template <typename T>
struct is_scoped_enum;

template <typename T>
inline constexpr bool is_scoped_enum_v = is_scoped_enum<T>::value;
  • Checks whether type is an Scoped enumeration.

  • Provides the member constant value which is equal to true, if T is an Scoped enumeration type.
    Otherwise, value is equal to false.

  • Examples

    magic_enum::is_scoped_enum<color>::value -> false
    magic_enum::is_scoped_enum<Direction>::value -> true
    
    // Helper variable template.
    magic_enum::is_scoped_enum_v<Direction> -> true

underlying_type

template <typename T>
struct underlying_type;

template <typename T>
using underlying_type_t = typename underlying_type<T>::type;
  • Improved UB-free "SFINAE-friendly" underlying_type.

  • If T is a complete enumeration type, provides a member typedef type that names the underlying type of T.
    Otherwise, if T is not an enumeration type, there is no member type.
    Otherwise (T is an incomplete enumeration type), the program is ill-formed.

  • Examples

    magic_enum::underlying_type<color>::type -> int
    
    // Helper types.
    magic_enum::underlying_type_t<Direction> -> int

ostream_operators

template <typename Char, typename Traits, typename E>
basic_ostream<Char, Traits>& operator<<(basic_ostream<Char, Traits>& os, E value);

template <typename Char, typename Traits, typename E>
basic_ostream<Char, Traits>& operator<<(basic_ostream<Char, Traits>& os, optional<E> value);
  • Out-of-the-box ostream operators for all enums.

  • Examples

    using namespace magic_enum::ostream_operators; // out-of-the-box ostream operators for enums.
    Color color = Color::BLUE;
    std::cout << color << std::endl; // "BLUE"

bitwise_operators

template <typename E>
constexpr E operator~(E rhs) noexcept;

template <typename E>
constexpr E operator|(E lhs, E rhs) noexcept;

template <typename E>
constexpr E operator&(E lhs, E rhs) noexcept;

template <typename E>
constexpr E operator^(E lhs, E rhs) noexcept;

template <typename E>
constexpr E& operator|=(E& lhs, E rhs) noexcept;

template <typename E>
constexpr E& operator&=(E& lhs, E rhs) noexcept;

template <typename E>
constexpr E& operator^=(E& lhs, E rhs) noexcept;
  • Out-of-the-box bitwise operators for all enums.

  • Examples

    enum class Flags { A = 1 << 0, B = 1 << 1, C = 1 << 2, D = 1 << 3 };
    using namespace magic_enum::bitwise_operators; // out-of-the-box bitwise operators for enums.
    // Support operators: ~, |, &, ^, |=, &=, ^=.
    Flags flags = Flags::A | Flags::B & ~Flags::C;

containers::array

template<typename E, typename V, typename Index = default_indexing<E>>
struct array {

  constexpr reference at(E pos);

  constexpr const_reference at(E pos) const;

  constexpr reference operator[](E pos) noexcept;

  constexpr const_reference operator[](E pos) const noexcept;

  constexpr reference front() noexcept;

  constexpr const_reference front() const noexcept;

  constexpr reference back() noexcept;

  constexpr const_reference back() const noexcept;

  constexpr pointer data() noexcept;

  constexpr const_pointer data() const noexcept;

  constexpr iterator begin() noexcept;

  constexpr const_iterator begin() const noexcept;

  constexpr const_iterator cbegin() const noexcept;

  constexpr iterator end() noexcept;

  constexpr const_iterator end() const noexcept;

  constexpr const_iterator cend() const noexcept;

  constexpr iterator rbegin() noexcept;

  constexpr const_iterator rbegin() const noexcept;

  constexpr const_iterator crbegin() const noexcept;

  constexpr iterator rend() noexcept;

  constexpr const_iterator rend() const noexcept;

  constexpr const_iterator crend() const noexcept;

  constexpr bool empty() const noexcept;

  constexpr size_type size() const noexcept;

  constexpr size_type max_size() const noexcept;

  constexpr void fill( const V& value );

  constexpr void swap(array& other) noexcept(std::is_nothrow_swappable_v<V>);

  friend constexpr bool operator==(const array& a1, const array& a2);

  friend constexpr bool operator!=(const array& a1, const array& a2);

  friend constexpr bool operator<(const array& a1, const array& a2);

  friend constexpr bool operator<=(const array& a1, const array& a2);

  friend constexpr bool operator>(const array& a1, const array& a2);

  friend constexpr bool operator>=(const array& a1, const array& a2);
}
  • STL like array for all enums.

  • Examples

    constexpr magic_enum::containers::array<Color, RGB> color_rgb_array {{{{255, 0, 0}, {0, 255, 0}, {0, 0, 255}}}};
    magic_enum::containers::array<Color, RGB> color_rgb_array {};
    color_rgb_array[Color::RED] = {255, 0, 0};
    color_rgb_array[Color::GREEN] = {0, 255, 0};
    color_rgb_array[Color::BLUE] = {0, 0, 255};
    std::get<Color::BLUE>(color_rgb_array) // -> RGB{0, 0, 255}

containers::bitset

template<typename E, typename Index = default_indexing<E>>
class bitset {

  constexpr explicit bitset(detail::raw_access_t = raw_access) noexcept;

  constexpr explicit bitset(detail::raw_access_t, unsigned long long val);

  constexpr explicit bitset(detail::raw_access_t,
                            string_view sv,
                            string_view::size_type pos = 0,
                            string_view::size_type n = string_view::npos,
                            char zero = '0',
                            char one = '1');

  constexpr explicit bitset(detail::raw_access_t,
                            const char* str,
                            std::size_t n = ~std::size_t{},
                            char zero = '0',
                            char one = '1');

  constexpr bitset(std::initializer_list<E> starters);

  template<typename V = E>
  constexpr explicit bitset(std::enable_if_t<magic_enum::detail::is_flags_v<V>, E> starter);

  template<typename Cmp = std::equal_to<>>
  constexpr explicit bitset(string_view sv,
                            Cmp&& cmp = {},
                            char sep = '|');

  friend constexpr bool operator==( const bitset& lhs, const bitset& rhs ) noexcept;

  friend constexpr bool operator!=( const bitset& lhs, const bitset& rhs ) noexcept;

  constexpr bool operator[](E pos) const noexcept;

  constexpr reference operator[](E pos) noexcept;

  constexpr bool test(E pos) const;

  constexpr bool all() const noexcept;

  constexpr bool any() const noexcept;

  constexpr bool none() const noexcept;

  constexpr std::size_t count() const noexcept;

  constexpr std::size_t size() const noexcept;

  constexpr std::size_t max_size() const noexcept;

  constexpr bitset& operator&= (const bitset& other) noexcept;

  constexpr bitset& operator|= (const bitset& other) noexcept;

  constexpr bitset& operator^= (const bitset& other) noexcept;

  constexpr bitset operator~() const noexcept;

  constexpr bitset& set() noexcept;

  constexpr bitset& set(E pos, bool value = true);

  constexpr bitset& reset() noexcept;

  constexpr bitset& reset(E pos);

  constexpr bitset& flip() noexcept;

  friend constexpr bitset operator&(const bitset& lhs, const bitset& rhs) noexcept;

  friend constexpr bitset operator|(const bitset& lhs, const bitset& rhs) noexcept;

  friend constexpr bitset operator^(const bitset& lhs, const bitset& rhs) noexcept;

  template<typename V = E>
  constexpr explicit operator std::enable_if_t<magic_enum::detail::is_flags_v<V>, E>() const;

  string to_string(char sep = '|') const;

  string to_string(detail::raw_access_t,
                                 char zero = '0',
                                 char one = '1') const;

  constexpr unsigned long long to_ullong(detail::raw_access_t raw) const;

  constexpr unsigned long long to_ulong(detail::raw_access_t raw) const;

  friend std::ostream& operator<<(std::ostream& o, const bitset& bs);

  friend std::istream& operator>>(std::istream& i, bitset& bs);
}
  • STL like bitset for all enums.

  • Examples

    constexpr magic_enum::containers::bitset<Color> color_bitset_red_green {Color::RED|Color::GREEN};
    bool all = color_bitset_red_green.all();
    // all -> false
    // Color::BLUE is missing
    bool test = color_bitset_red_green.test(Color::RED);
    // test -> true
    auto color_bitset = magic_enum::containers::bitset<Color>();
    color_bitset.set(Color::GREEN);
    color_bitset.set(Color::BLUE);
    std::string to_string = color_bitset.to_string();
    // to_string -> "GREEN|BLUE"

containers::set

template<typename E, typename CExprLess = std::less<E>>
class set {

  constexpr set() noexcept = default;

  template<typename InputIt>
  constexpr set(InputIt first, InputIt last);

  constexpr set(std::initializer_list<E> ilist);

  template<typename V = E>
  constexpr explicit set(std::enable_if_t<magic_enum::detail::is_flags_v<V>, E> starter);

  constexpr set(const set&) noexcept = default;

  constexpr set(set&&) noexcept = default;

  constexpr set& operator=(const set&) noexcept = default;

  constexpr set& operator=(set&&) noexcept = default;

  constexpr set& operator=(std::initializer_list<E> ilist);

  constexpr const_iterator begin() const noexcept;

  constexpr const_iterator end() const noexcept;

  constexpr const_iterator cbegin() const noexcept;

  constexpr const_iterator cend() const noexcept;

  constexpr const_reverse_iterator rbegin() const noexcept;

  constexpr const_reverse_iterator rend() const noexcept;

  constexpr const_reverse_iterator crbegin() const noexcept;

  constexpr const_reverse_iterator crend() const noexcept;

  constexpr bool empty() const noexcept;

  constexpr size_type size() const noexcept;

  constexpr size_type max_size() const noexcept;

  constexpr void clear() noexcept;

  constexpr std::pair<iterator,bool> insert(const value_type& value) noexcept;

  constexpr std::pair<iterator,bool> insert(value_type&& value) noexcept;

  constexpr iterator insert(const_iterator, const value_type& value) noexcept;

  constexpr iterator insert(const_iterator hint, value_type&& value) noexcept;

  template< class InputIt >
  constexpr void insert(InputIt first, InputIt last) noexcept;

  constexpr void insert(std::initializer_list<value_type> ilist) noexcept;

  template<class... Args>
  constexpr std::pair<iterator,bool> emplace(Args&&... args) noexcept;

  template<class... Args>
  constexpr iterator emplace_hint(const_iterator, Args&&... args) noexcept;

  constexpr iterator erase(const_iterator pos) noexcept;

  constexpr iterator erase(const_iterator first, const_iterator last) noexcept;

  constexpr size_type erase(const key_type& key) noexcept;

  template<class K, typename KC = key_compare>
  constexpr std::enable_if_t<detail::is_transparent_v<KC>, size_type> erase(K&& x) noexcept;

  void swap(set& other) noexcept;

  constexpr size_type count(const key_type& key) const noexcept;

  template<typename K, typename KC = key_compare>
  constexpr std::enable_if_t<detail::is_transparent_v<KC>, size_type> count(const K& x) const;

  constexpr const_iterator find(const key_type & key) const noexcept;

  template<class K, typename KC = key_compare>
  constexpr std::enable_if_t<detail::is_transparent_v<KC>, const_iterator> find(const K& x) const;

  constexpr bool contains(const key_type& key) const noexcept;

  template<typename K, typename KC = key_compare>
  constexpr std::enable_if_t<detail::is_transparent_v<KC>, bool> contains(const K& x) const noexcept;

  constexpr std::pair<const_iterator,const_iterator> equal_range(const key_type& key) const noexcept;

  template<typename K, typename KC = key_compare>
  constexpr std::enable_if_t<detail::is_transparent_v<KC>, std::pair<const_iterator,const_iterator>> equal_range(const K& x) const noexcept;

  constexpr const_iterator lower_bound(const key_type& key) const noexcept;

  template<typename K, typename KC = key_compare>
  constexpr std::enable_if_t<detail::is_transparent_v<KC>, const_iterator> lower_bound(const K& x) const noexcept;

  constexpr const_iterator upper_bound(const key_type& key) const noexcept;

  template<typename K, typename KC = key_compare>
  constexpr std::enable_if_t<detail::is_transparent_v<KC>, const_iterator> upper_bound(const K& x) const noexcept;

  constexpr key_compare key_comp() const;

  constexpr value_compare value_comp() const;

  constexpr friend bool operator==(const set& lhs, const set& rhs) noexcept;

  constexpr friend bool operator!=(const set& lhs, const set& rhs) noexcept;

  constexpr friend bool operator<(const set& lhs, const set& rhs) noexcept;

  constexpr friend bool operator<=(const set& lhs, const set& rhs) noexcept;

  constexpr friend bool operator>(const set& lhs, const set& rhs) noexcept;

  constexpr friend bool operator>=(const set& lhs, const set& rhs) noexcept;

  template<typename Pred>
  size_type erase_if(Pred pred);
}
  • STL like set for all enums.

  • Examples

    constexpr magic_enum::containers::set color_set_filled = {Color::RED, Color::GREEN, Color::BLUE};
    auto color_set = magic_enum::containers::set<Color>();
    bool empty = color_set.empty();
    // empty -> true
    color_set.insert(Color::GREEN);
    color_set.insert(Color::BLUE);
    color_set.insert(Color::RED);
    std::size_t size = color_set.size();
    // size -> 3