C++ concepts: DefaultInsertable

 

C++

Language

Standard library headers

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

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Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Technical Specifications

 

C++ concepts

Basic
DefaultConstructible CopyAssignable CopyConstructible	MoveAssignable (C++11) MoveConstructible (C++11) Destructible
Layout
TrivialType (C++11) TriviallyCopyable (C++11)	StandardLayoutType (C++11) PODType
Library-Wide
EqualityComparable LessThanComparable Swappable (C++11) ValueSwappable (C++11)	NullablePointer (C++11) Hash (C++11) Allocator
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
Iterator OutputIterator InputIterator	ForwardIterator BidirectionalIterator RandomAccessIterator ContiguousIterator (C++17)
Stream I/O
FormattedInputFunction UnformattedInputFunction	FormattedOutputFunction UnformattedOutputFunction
Random Numbers
SeedSequence (C++11) RandomNumberEngine (C++11)	RandomNumberDistribution (C++11) UniformRandomNumberGenerator (C++11) RandomNumberEngineAdaptor (C++11)
Concurrency
BasicLockable (C++11) Lockable (C++11) TimedLockable (C++11)	Mutex (C++11) TimedMutex (C++11) SharedMutex (C++17) SharedTimedMutex (C++14)
Other
CharTraits pos_type off_type Clock (C++11) BitmaskType	UnaryTypeTrait (C++11) BinaryTypeTrait (C++11) TransformationTrait (C++11) TrivialClock (C++11) LiteralType (C++11)

 

Specifies that an instance of the type can be default-constructed in-place, in uninitialized storage.

Requirements

The type T is DefaultInsertable into the Container X if, given

A	the allocator type defined as X::allocator_type
m	the lvalue of type A obtained from X::get_allocator()
p	the pointer of type T* prepared by the container

the following expression is well-formed:

std::allocator_traits<A>::construct(m, p);

Notes

By default, this will call placement-new, as by ::new((void*)p) T() (that is, value-initialize the object pointed to by p). If value-initialization is undesirable, for example, if the object is of non-class type and zeroing out is not needed, it can be avoided by providing a custom Allocator::construct.

See Also

DefaultConstructible

CopyInsertable

MoveInsertable

EmplaceConstructible

Erasable