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Header-only C++17 library provides nameof macros and functions to simply obtain the name of a variable, type, function, macro, and enum.
- C++17
- Header-only
- Dependency-free
- Compile-time
- Name of variable, member variable
- Name of type, variable type
- Name of function, member function
- Name of enum, enum variable
- Name of macro
- Enum to string
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Nameof
// Name of variable. NAMEOF(somevar) -> "somevar" // Name of member variable. NAMEOF(person.address.zip_code) -> "zip_code" // Name of function. NAMEOF(foo<int, float>()) -> "foo" // Name of member function. NAMEOF(somevar.some_method()) -> "some_method" NAMEOF(somevar.some_method<int>()) -> "some_method" // Name of macro. NAMEOF(__LINE__) -> "__LINE__" NAMEOF(NAMEOF(structvar)) -> "NAMEOF"
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Nameof enum
auto color = Color::RED; // Name of enum variable. NAMEOF_ENUM(color) -> "RED" nameof::nameof_enum(color) -> "RED" // Static storage enum variable to string. // This version is much lighter on the compile times and is not restricted to the enum_range limitation. NAMEOF_CONST_ENUM(Color::GREEN) -> "GREEN" nameof::nameof_enum<Color::GREEN>() -> "GREEN"
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Nameof type
using T = const int&; T var = 42; // Name of variable type. NAMEOF_TYPE_EXPR(var) -> "int" NAMEOF_FULL_TYPE_EXPR(var) -> "const int&" nameof::nameof_type<decltype(var)>() -> "int" nameof::nameof_full_type<decltype(var)>() -> "const int&" // Name of type. NAMEOF_TYPE(T) -> "int" NAMEOF_FULL_TYPE(T) -> "const int&" nameof::nameof_type<T>() -> "int" nameof::nameof_full_type<T>() -> "const int&"
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Compile-time
constexpr auto somevar_name = NAMEOF(somevar); // somevar_name -> "somevar" constexpr auto color_name = NAMEOF_ENUM(Color::BLUE); // or nameof::nameof_enum(Color::BLUE) // color_name -> "BLUE" constexpr auto var_type_name = NAMEOF_TYPE_EXPR(var); // or nameof::nameof_type<decltype(var)>() // var_type_name -> "int" constexpr auto type_name = NAMEOF_TYPE(T); // or nameof::nameof_type<T>() // type_name -> "int"
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Nameof returns
std::string_view
. If argument does not have name, returns empty string. -
Nameof expression argument are identified, but are not evaluated.
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Nameof type returns compiler-specific type name. In all cases, reference and cv-qualifiers are ignored by
nameof_type
(that is,nameof_type<const T&>() == nameof_type<T>()
). If you need detailed name of full type, usenameof_full_type
. -
If you need name with template suffix, use NAMEOF_FULL.
// Full name of template function. NAMEOF_FULL(foo<int, float>()) -> "foo<int, float>" // Full name of template member function. NAMEOF_FULL(somevar.some_method<int>()) -> "some_method<int>"
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If you need raw fully-qualified name, use NAMEOF_RAW.
NAMEOF_RAW(::somevar.somefield) -> "::somevar.somefield" NAMEOF_RAW(&some_class::some_method<int>) -> "&some_class::some_method<int>"
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Enum value must be in range
[NAMEOF_ENUM_RANGE_MIN, NAMEOF_ENUM_RANGE_MAX]
. By defaultNAMEOF_ENUM_RANGE_MIN = -128
,NAMEOF_ENUM_RANGE_MAX = 128
.If need another range for all enum types by default, redefine the macro
NAMEOF_ENUM_RANGE_MIN
andNAMEOF_ENUM_RANGE_MAX
.#define NAMEOF_ENUM_RANGE_MIN 0 #define NAMEOF_ENUM_RANGE_MAX 256 #include <nameof.hpp>
If need another range for specific enum type, add specialization
enum_range
for necessary enum type.#include <nameof.hpp> enum number { one = 100, two = 200, three = 300 }; namespace nameof { template <> struct enum_range<number> { static constexpr int min = 100; static constexpr int max = 300; }; }
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Nameof enum obtains the first defined value enums, and won't work if value are aliased.
enum ShapeKind { ConvexBegin = 0, Box = 0, // Won't work. Sphere = 1, ConvexEnd = 2, Donut = 2, // Won't work too. Banana = 3, COUNT = 4, }; // NAMEOF_ENUM(ShapeKind::Box) -> "ConvexBegin" // nameof::nameof_enum(ShapeKind::Box) -> "ConvexBegin"
Work around the issue:
enum ShapeKind { // Convex shapes, see ConvexBegin and ConvexEnd below. Box = 0, Sphere = 1, // Non-convex shapes. Donut = 2, Banana = 3, COUNT = Banana + 1, // Non-reflected aliases. ConvexBegin = Box, ConvexEnd = Sphere + 1, }; // NAMEOF_ENUM(ShapeKind::Box) -> "Box" // nameof::nameof_enum(ShapeKind::Box) -> "Box" // Non-reflected aliases. // NAMEOF_ENUM(ShapeKind::ConvexBegin) -> "Box" // nameof::nameof_enum(ShapeKind::ConvexBegin) -> "Box"
You should add required file nameof.hpp.
- Clang/LLVM >= 5
- Visual C++ >= 15.3 / Visual Studio >= 2017
- Xcode >= 9
- GCC >= 7 (GCC >= 9 for NAMEOF_ENUM)