C++ named requirements: CopyConstructible

 

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C++ named requirements

Basic
DefaultConstructible CopyAssignable CopyConstructible	MoveAssignable (C++11) MoveConstructible (C++11) Destructible
Type properties
ScalarType TriviallyCopyable (C++11) StandardLayoutType (C++11)	PODType TrivialType (C++11) ImplicitLifetimeType (C++20)
Library-Wide
EqualityComparable LessThanComparable Swappable (C++11) ValueSwappable (C++11) NullablePointer (C++11) Hash (C++11)	Allocator FunctionObject Callable Predicate BinaryPredicate Compare
Container
Container SequenceContainer ContiguousContainer (C++17) ReversibleContainer	AssociativeContainer AllocatorAwareContainer UnorderedAssociativeContainer (C++11)
Container Elements
DefaultInsertable (C++11) CopyInsertable (C++11) MoveInsertable (C++11)	EmplaceConstructible (C++11) Erasable (C++11)
Iterator
LegacyIterator LegacyOutputIterator LegacyInputIterator LegacyForwardIterator	LegacyBidirectionalIterator LegacyRandomAccessIterator LegacyContiguousIterator (C++17) ConstexprIterator (C++20)
Stream I/O
FormattedInputFunction UnformattedInputFunction	FormattedOutputFunction UnformattedOutputFunction
Formatting
BasicFormatter (C++20)	Formatter (C++20)
Random Numbers
SeedSequence (C++11) RandomNumberEngine (C++11)	RandomNumberDistribution (C++11) UniformRandomBitGenerator (C++11) RandomNumberEngineAdaptor (C++11)
Concurrency
BasicLockable (C++11) Lockable (C++11) TimedLockable (C++11) SharedLockable (C++14) SharedTimedLockable (C++14)	Mutex (C++11) TimedMutex (C++11) SharedMutex (C++17) SharedTimedMutex (C++14)
Other
CharTraits RegexTraits (C++11) BitmaskType NumericType LiteralType (C++11)	UnaryTypeTrait (C++11) BinaryTypeTrait (C++11) TransformationTrait (C++11) Clock (C++11) TrivialClock (C++11)

 

Specifies that an instance of the type can be copy-constructed from an lvalue expression.

Requirements

The type T satisfies CopyConstructible if

• The type T satisfies MoveConstructible, and

Given

• v, an lvalue expression of type T or const T or an rvalue expression of type const T
• u, an arbitrary identifier

The following expressions must be valid and have their specified effects

Expression	Post-conditions
T u = v;	The value of u is equivalent to the value of v. The value of v is unchanged
T(v)	The value of T(v) is equivalent to the value of v. The value of v is unchanged.

The expression v.~T() also must be valid, and, for lvalue v, the expression &v must have the type T* or const T* and must evaluate to the address of v

(until C++11)

Notes

Until C++11, classes that overloaded operator& were not CopyConstructible and thus weren't usable in the standard library containers. As of C++11, the standard library uses std::addressof whenever the address of an object is needed.

See also

is_copy_constructibleis_trivially_copy_constructibleis_nothrow_copy_constructible (C++11)(C++11)(C++11)	checks if a type has a copy constructor (class template)
copy_constructible (C++20)	specifies that an object of a type can be copy constructed and move constructed (concept)