C++ keyword: union

 

C++

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Technical specifications

Symbols index

External libraries

 

C++ language

General topics
Preprocessor Comments	Keywords Escape sequences
Flow control
Conditional execution statements
if	switch
Iteration statements (loops)
for range-for (C++11)	while do-while
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continue - break	goto - return
Functions
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inline specifier
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throw-expression	try-catch block
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Specifiers
decltype (C++11) auto (C++11) alignas (C++11)	const/volatile constexpr (C++11)
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Initialization
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Boolean - Integer - Floating-point
Character - String - nullptr (C++11)
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Types
typedef declaration
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static_cast - dynamic_cast
const_cast - reinterpret_cast
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new expression	delete expression
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Virtual function override specifier (C++11)       final specifier (C++11)	explicit (C++11) static
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Templates
Class template Function template	Template specialization Parameter packs (C++11)
Miscellaneous
Inline assembly	History of C++

 

Keywords

alignas (C++11) alignof (C++11) and and_eq asm auto (*) bitand bitor bool break case catch char char8_t (C++20) char16_t (C++11) char32_t (C++11) class compl concept (C++20) const consteval (C++20)     constexpr (C++11) constinit (C++20) const_cast continue co_await (C++20) co_return (C++20) co_yield (C++20) decltype (C++11) default delete	do double dynamic_cast else enum explicit export extern false float for friend goto if inline int long mutable namespace new noexcept (C++11)     not not_eq nullptr (C++11) operator or or_eq private protected public register	reinterpret_cast requires (C++20) return short signed sizeof (*) static static_assert (C++11) static_cast struct switch template this thread_local (C++11) throw true try typedef typeid typename union unsigned using virtual void volatile wchar_t while xor xor_eq
Identifiers with special meaning
final (C++11) import (C++20)	module (C++20) override (C++11)

 

Usage

• declaration of a union type
• If a function or a variable exists in scope with the name identical to the name of a union type, union can be prepended to the name for disambiguation, resulting in an elaborated type specifier