std::pair - Man Page

Struct holding two objects of arbitrary type.

Synopsis

#include <utility>

Inherits __pair_base< _T1, _T2 >.

Inherited by std::sub_match< _Bi_iter >.

Public Types

typedef _T1 first_type
The type of the first member.
typedef _T2 second_type
The type of the second member.

Public Member Functions

template<typename _U1  = _T1, typename _U2  = _T2, typename enable_if< __and_< __is_implicitly_default_constructible< _U1 >, __is_implicitly_default_constructible< _U2 > > ::value, bool >::type  = true> constexpr pair ()
template<typename _U2 , __enable_if_t< __and_< is_pointer< _T1 >, __not_< is_reference< _U2 > >, is_constructible< _T2, _U2 >, __not_< is_constructible< _T2, const _U2 & > >, is_convertible< _U2, _T2 > >::value, bool >  = true> constexpr pair (__zero_as_null_pointer_constant, _U2 &&__y,...)
template<typename _U2 , __enable_if_t< __and_< is_pointer< _T1 >, __not_< is_reference< _U2 > >, is_constructible< _T2, _U2 >, __not_< is_constructible< _T2, const _U2 & > >, __not_< is_convertible< _U2, _T2 > > >::value, bool >  = false> constexpr pair (__zero_as_null_pointer_constant, _U2 &&__y,...)
template<typename _U1 , __enable_if_t< __and_< __not_< is_reference< _U1 > >, is_pointer< _T2 >, is_constructible< _T1, _U1 >, __not_< is_constructible< _T1, const _U1 & > >, is_convertible< _U1, _T1 > >::value, bool >  = true> constexpr pair (_U1 &&__x, __zero_as_null_pointer_constant,...)
template<typename _U1 , __enable_if_t< __and_< __not_< is_reference< _U1 > >, is_pointer< _T2 >, is_constructible< _T1, _U1 >, __not_< is_constructible< _T1, const _U1 & > >, __not_< is_convertible< _U1, _T1 > > >::value, bool >  = false> constexpr pair (_U1 &&__x, __zero_as_null_pointer_constant,...)
template<typename _U1 , typename _U2 , typename enable_if< _PCCP::template _MoveConstructiblePair< _U1, _U2 >() &&_PCCP::template _ImplicitlyMoveConvertiblePair< _U1, _U2 >(), bool >::type  = true> constexpr pair (_U1 &&__x, _U2 &&__y)
template<typename _U1 , typename _U2 , typename enable_if< _PCCP::template _MoveConstructiblePair< _U1, _U2 >() &&!_PCCP::template _ImplicitlyMoveConvertiblePair< _U1, _U2 >(), bool >::type  = false> constexpr pair (_U1 &&__x, _U2 &&__y)
template<typename _U1  = _T1, typename _U2  = _T2, typename enable_if< _PCCP::template _ConstructiblePair< _U1, _U2 >() &&_PCCP::template _ImplicitlyConvertiblePair< _U1, _U2 >(), bool >::type  = true> constexpr pair (const _T1 &__a, const _T2 &__b)
Construct from two const lvalues, allowing implicit conversions.
template<typename _U1  = _T1, typename _U2  = _T2, typename enable_if< _PCCP::template _ConstructiblePair< _U1, _U2 >() &&!_PCCP::template _ImplicitlyConvertiblePair< _U1, _U2 >(), bool >::type  = false> constexpr pair (const _T1 &__a, const _T2 &__b)
Construct from two const lvalues, disallowing implicit conversions.
constexpr pair (const pair &)=default
Copy constructor.
template<typename _U1 , typename _U2 , typename enable_if< _PCCFP< _U1, _U2 >::template _ConstructiblePair< _U1, _U2 >() &&_PCCFP< _U1, _U2 >::template _ImplicitlyConvertiblePair< _U1, _U2 >(), bool >::type  = true> constexpr pair (const pair< _U1, _U2 > &__p)
template<typename _U1 , typename _U2 , typename enable_if< _PCCFP< _U1, _U2 >::template _ConstructiblePair< _U1, _U2 >() &&!_PCCFP< _U1, _U2 >::template _ImplicitlyConvertiblePair< _U1, _U2 >(), bool >::type  = false> constexpr pair (const pair< _U1, _U2 > &__p)
constexpr pair (pair &&)=default
Move constructor.
template<typename _U1 , typename _U2 , typename enable_if< _PCCFP< _U1, _U2 >::template _MoveConstructiblePair< _U1, _U2 >() &&_PCCFP< _U1, _U2 >::template _ImplicitlyMoveConvertiblePair< _U1, _U2 >(), bool >::type  = true> constexpr pair (pair< _U1, _U2 > &&__p)
template<typename _U1 , typename _U2 , typename enable_if< _PCCFP< _U1, _U2 >::template _MoveConstructiblePair< _U1, _U2 >() &&!_PCCFP< _U1, _U2 >::template _ImplicitlyMoveConvertiblePair< _U1, _U2 >(), bool >::type  = false> constexpr pair (pair< _U1, _U2 > &&__p)
template<typename... _Args1, typename... _Args2> constexpr pair (piecewise_construct_t, tuple< _Args1... >, tuple< _Args2... >)
pair & operator= (__conditional_t< __and_< is_copy_assignable< _T1 >, is_copy_assignable< _T2 > >::value, const pair &, const __nonesuch & > __p)
pair & operator= (__conditional_t< __and_< is_move_assignable< _T1 >, is_move_assignable< _T2 > >::value, pair &&, __nonesuch && > __p) noexcept(__and_< is_nothrow_move_assignable< _T1 >, is_nothrow_move_assignable< _T2 > >::value)
template<typename _U1 , typename _U2 > enable_if< __and_< is_assignable< _T1 &, const_U1 & >, is_assignable< _T2 &, const_U2 & > >::value, pair & >::type operator= (const pair< _U1, _U2 > &__p)
template<typename _U1 , typename _U2 > enable_if< __and_< is_assignable< _T1 &, _U1 && >, is_assignable< _T2 &, _U2 && > >::value, pair & >::type operator= (pair< _U1, _U2 > &&__p)
constexpr void swap (pair &__p) noexcept(__and_< __is_nothrow_swappable< _T1 >, __is_nothrow_swappable< _T2 > >::value)
Swap the first members and then the second members.

Public Attributes

_T1 first
The first member.
_T2 second
The second member.

Detailed Description

template<typename _T1, typename _T2>

struct std::pair< _T1, _T2 >"Struct holding two objects of arbitrary type.

Template Parameters

_T1 Type of first object.
_T2 Type of second object.

https://gcc.gnu.org/onlinedocs/libstdc++/manual/utilities.html

Definition at line 185 of file utility.

Member Typedef Documentation

template<typename _T1 , typename _T2 > typedef _T1 std::pair< _T1, _T2 >::first_type

The type of the first member.

Definition at line 188 of file utility.

template<typename _T1 , typename _T2 > typedef _T2 std::pair< _T1, _T2 >::second_type

The type of the second member.

Definition at line 189 of file utility.

Constructor & Destructor Documentation

template<typename _T1 , typename _T2 > constexpr std::pair< _T1, _T2 >::pair (const pair< _T1, _T2 > &) [constexpr], [default]

Copy constructor.

template<typename _T1 , typename _T2 > constexpr std::pair< _T1, _T2 >::pair (pair< _T1, _T2 > &&) [constexpr], [default]

Move constructor.

template<typename _T1 , typename _T2 > template<typename _U1  = _T1, typename _U2  = _T2, typename enable_if< __and_< __is_implicitly_default_constructible< _U1 >, __is_implicitly_default_constructible< _U2 > > ::value, bool >::type  = true> constexpr std::pair< _T1, _T2 >::pair () [inline], [constexpr]

The default constructor creates first and second using their respective default constructors.

Definition at line 384 of file utility.

template<typename _T1 , typename _T2 > template<typename _U1  = _T1, typename _U2  = _T2, typename enable_if< __and_< is_default_constructible< _U1 >, is_default_constructible< _U2 >, __not_< __and_< __is_implicitly_default_constructible< _U1 >, __is_implicitly_default_constructible< _U2 > > > > ::value, bool >::type  = false> constexpr std::pair< _T1, _T2 >::pair () [inline], [explicit], [constexpr]

Definition at line 396 of file utility.

template<typename _T1 , typename _T2 > template<typename _U1  = _T1, typename _U2  = _T2, typename enable_if< _PCCP::template _ConstructiblePair< _U1, _U2 >() &&_PCCP::template _ImplicitlyConvertiblePair< _U1, _U2 >(), bool >::type  = true> constexpr std::pair< _T1, _T2 >::pair (const _T1 & __a, const _T2 & __b) [inline], [constexpr]

Construct from two const lvalues, allowing implicit conversions.

Definition at line 411 of file utility.

template<typename _T1 , typename _T2 > template<typename _U1  = _T1, typename _U2  = _T2, typename enable_if< _PCCP::template _ConstructiblePair< _U1, _U2 >() &&!_PCCP::template _ImplicitlyConvertiblePair< _U1, _U2 >(), bool >::type  = false> constexpr std::pair< _T1, _T2 >::pair (const _T1 & __a, const _T2 & __b) [inline], [explicit], [constexpr]

Construct from two const lvalues, disallowing implicit conversions.

Definition at line 421 of file utility.

template<typename _T1 , typename _T2 > template<typename _U1 , typename _U2 , typename enable_if< _PCCFP< _U1, _U2 >::template _ConstructiblePair< _U1, _U2 >() &&_PCCFP< _U1, _U2 >::template _ImplicitlyConvertiblePair< _U1, _U2 >(), bool >::type  = true> constexpr std::pair< _T1, _T2 >::pair (const pair< _U1, _U2 > & __p) [inline], [constexpr]

Definition at line 438 of file utility.

template<typename _T1 , typename _T2 > template<typename _U1 , typename _U2 , typename enable_if< _PCCFP< _U1, _U2 >::template _ConstructiblePair< _U1, _U2 >() &&!_PCCFP< _U1, _U2 >::template _ImplicitlyConvertiblePair< _U1, _U2 >(), bool >::type  = false> constexpr std::pair< _T1, _T2 >::pair (const pair< _U1, _U2 > & __p) [inline], [explicit], [constexpr]

Definition at line 447 of file utility.

template<typename _T1 , typename _T2 > template<typename _U1 , __enable_if_t< __and_< __not_< is_reference< _U1 > >, is_pointer< _T2 >, is_constructible< _T1, _U1 >, __not_< is_constructible< _T1, const _U1 & > >, is_convertible< _U1, _T1 > >::value, bool >  = true> constexpr std::pair< _T1, _T2 >::pair (_U1 && __x, __zero_as_null_pointer_constant,  ...) [inline], [constexpr]

Definition at line 487 of file utility.

template<typename _T1 , typename _T2 > template<typename _U1 , __enable_if_t< __and_< __not_< is_reference< _U1 > >, is_pointer< _T2 >, is_constructible< _T1, _U1 >, __not_< is_constructible< _T1, const _U1 & > >, __not_< is_convertible< _U1, _T1 > > >::value, bool >  = false> constexpr std::pair< _T1, _T2 >::pair (_U1 && __x, __zero_as_null_pointer_constant,  ...) [inline], [explicit], [constexpr]

Definition at line 499 of file utility.

template<typename _T1 , typename _T2 > template<typename _U2 , __enable_if_t< __and_< is_pointer< _T1 >, __not_< is_reference< _U2 > >, is_constructible< _T2, _U2 >, __not_< is_constructible< _T2, const _U2 & > >, is_convertible< _U2, _T2 > >::value, bool >  = true> constexpr std::pair< _T1, _T2 >::pair (__zero_as_null_pointer_constant, _U2 && __y,  ...) [inline], [constexpr]

Definition at line 511 of file utility.

template<typename _T1 , typename _T2 > template<typename _U2 , __enable_if_t< __and_< is_pointer< _T1 >, __not_< is_reference< _U2 > >, is_constructible< _T2, _U2 >, __not_< is_constructible< _T2, const _U2 & > >, __not_< is_convertible< _U2, _T2 > > >::value, bool >  = false> constexpr std::pair< _T1, _T2 >::pair (__zero_as_null_pointer_constant, _U2 && __y,  ...) [inline], [explicit], [constexpr]

Definition at line 523 of file utility.

template<typename _T1 , typename _T2 > template<typename _U1 , typename _U2 , typename enable_if< _PCCP::template _MoveConstructiblePair< _U1, _U2 >() &&_PCCP::template _ImplicitlyMoveConvertiblePair< _U1, _U2 >(), bool >::type  = true> constexpr std::pair< _T1, _T2 >::pair (_U1 && __x, _U2 && __y) [inline], [constexpr]

Definition at line 534 of file utility.

template<typename _T1 , typename _T2 > template<typename _U1 , typename _U2 , typename enable_if< _PCCP::template _MoveConstructiblePair< _U1, _U2 >() &&!_PCCP::template _ImplicitlyMoveConvertiblePair< _U1, _U2 >(), bool >::type  = false> constexpr std::pair< _T1, _T2 >::pair (_U1 && __x, _U2 && __y) [inline], [explicit], [constexpr]

Definition at line 543 of file utility.

template<typename _T1 , typename _T2 > template<typename _U1 , typename _U2 , typename enable_if< _PCCFP< _U1, _U2 >::template _MoveConstructiblePair< _U1, _U2 >() &&_PCCFP< _U1, _U2 >::template _ImplicitlyMoveConvertiblePair< _U1, _U2 >(), bool >::type  = true> constexpr std::pair< _T1, _T2 >::pair (pair< _U1, _U2 > && __p) [inline], [constexpr]

Definition at line 553 of file utility.

template<typename _T1 , typename _T2 > template<typename _U1 , typename _U2 , typename enable_if< _PCCFP< _U1, _U2 >::template _MoveConstructiblePair< _U1, _U2 >() &&!_PCCFP< _U1, _U2 >::template _ImplicitlyMoveConvertiblePair< _U1, _U2 >(), bool >::type  = false> constexpr std::pair< _T1, _T2 >::pair (pair< _U1, _U2 > && __p) [inline], [explicit], [constexpr]

Definition at line 563 of file utility.

Member Function Documentation

template<typename _T1 , typename _T2 > pair & std::pair< _T1, _T2 >::operator= (__conditional_t< __and_< is_copy_assignable< _T1 >, is_copy_assignable< _T2 > >::value, const pair< _T1, _T2 > &, const __nonesuch & > __p) [inline]

Definition at line 568 of file utility.

template<typename _T1 , typename _T2 > pair & std::pair< _T1, _T2 >::operator= (__conditional_t< __and_< is_move_assignable< _T1 >, is_move_assignable< _T2 > >::value, pair< _T1, _T2 > &&, __nonesuch && > __p) [inline], [noexcept]

Definition at line 578 of file utility.

template<typename _T1 , typename _T2 > template<typename _U1 , typename _U2 > enable_if< __and_< is_assignable< _T1 &, const_U1 & >, is_assignable< _T2 &, const_U2 & > >::value, pair & >::type std::pair< _T1, _T2 >::operator= (const pair< _U1, _U2 > & __p) [inline]

Definition at line 593 of file utility.

template<typename _T1 , typename _T2 > template<typename _U1 , typename _U2 > enable_if< __and_< is_assignable< _T1 &, _U1 && >, is_assignable< _T2 &, _U2 && > >::value, pair & >::type std::pair< _T1, _T2 >::operator= (pair< _U1, _U2 > && __p) [inline]

Definition at line 604 of file utility.

template<typename _T1 , typename _T2 > constexpr void std::pair< _T1, _T2 >::swap (pair< _T1, _T2 > & __p) [inline], [constexpr], [noexcept]

Swap the first members and then the second members.

Definition at line 204 of file utility.

References std::pair< _T1, _T2 >::first, std::pair< _T1, _T2 >::second, std::swap(), and std::pair< _T1, _T2 >::swap().

Referenced by std::swap(), and std::pair< _T1, _T2 >::swap().

Member Data Documentation

template<typename _T1 , typename _T2 > _T1 std::pair< _T1, _T2 >::first

The first member.

Definition at line 191 of file utility.

Referenced by std::_Temporary_buffer< _ForwardIterator, _Tp >::_Temporary_buffer(), __gnu_parallel::__find_template(), std::__sample(), std::set< _Key, _Compare, _Alloc >::insert(), std::pair< _T1, _T2 >::operator<(), std::pair< _T1, _T2 >::operator==(), std::shuffle(), and std::pair< _T1, _T2 >::swap().

template<typename _T1 , typename _T2 > _T2 std::pair< _T1, _T2 >::second

The second member.

Definition at line 192 of file utility.

Referenced by std::_Temporary_buffer< _ForwardIterator, _Tp >::_Temporary_buffer(), std::__sample(), std::set< _Key, _Compare, _Alloc >::insert(), std::pair< _T1, _T2 >::operator<(), std::pair< _T1, _T2 >::operator==(), std::shuffle(), and std::pair< _T1, _T2 >::swap().

Author

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Wed Sep 7 2022 libstdc++