Aug 14, 2024 · 3) Opaque enum declaration: defines the enumeration type but not its enumerators: after this declaration, the type is a complete type and its size is known. ... There are two distinct kinds of enumerations: unscoped enumeration (declared with the enum-keyenum) and scoped enumeration (declared with the enum-keyenum class or enum struct).

May 16, 2024 · The identifier itself, if used, becomes the name of the enumerated type in the tags name space and requires the use of the keyword enum (unless typedef'd into the ordinary name space).

Aug 14, 2024 · declaration of a scoped enumeration type (since C++11)See also struct class

Aug 26, 2023 · std::is_enum is a UnaryTypeTrait. Checks whether T is an enumeration type. Provides the member constant value which is equal to true, if T is an enumeration type. Otherwise, value is equal to false. If the program adds specializations for std::is_enum or std::is_enum_v, the behavior is undefined.

May 14, 2013 · [edit] Keywords alignas (C23) alignof (C23) auto bool (C23) break case char const constexpr (C23) continue default do double else enum

Sep 12, 2023 · Return value The integer value of the underlying type of Enum, converted from e.

Apr 17, 2025 · 2) Elaborated type specifier for an enumeration type. 3) A declaration that consists solely of an elaborated type specifier always declares a class type named by identifier in the scope that contains the declaration. Opaque enum declaration resembles form (3), but the enum type is a complete type after an opaque enum declaration.

Jan 25, 2025 · Empty declarators are prohibited; a simple declaration must have at least one declarator or declare at least one struct/union/enum tag, or introduce at least one enumeration constant. If any part of a declarator is a variable-length array (VLA) declarator, the entire declarator's type is known as "variably-modified type".

Aug 14, 2024 · Usage using-directives for namespaces and using-declarations for namespace members using-declarations for class members using-enum-declarations for enumerators (since C++20) type alias and alias template declaration (since C++11)

Dec 6, 2021 · 2) identifier that follows the keyword struct, union, or enum is looked up in the tag name space. 3) identifier that follows the member access or member access through pointer operator is looked up in the name space of members of the type determined by the left-hand operand of the member access operator.