Iterator for rows in a result. Use as result::const_iterator. More...

#include <result_iterator.hxx>

Inheritance diagram for pqxx::const_result_iterator:

Public Types
using	iterator_category = std::random_access_iterator_tag

using	value_type = const row

using	pointer = const row *

using	reference = row

using	size_type = result_size_type

using	difference_type = result_difference_type

Public Types inherited from pqxx::row
using	size_type = row_size_type

using	difference_type = row_difference_type

using	const_iterator = const_row_iterator

using	iterator = const_iterator

using	reference = field

using	pointer = const_row_iterator

using	const_reverse_iterator = const_reverse_row_iterator

using	reverse_iterator = const_reverse_iterator

Public Member Functions
	const_result_iterator () noexcept

	const_result_iterator (const row &t) noexcept

Dereferencing operators
pointer	operator-> () const

reference	operator* () const

Manipulations
const_result_iterator	operator++ (int)

const_result_iterator &	operator++ ()

const_result_iterator	operator-- (int)

const_result_iterator &	operator-- ()

const_result_iterator &	operator+= (difference_type i)

const_result_iterator &	operator-= (difference_type i)

Comparisons
bool	operator== (const const_result_iterator &i) const

bool	operator!= (const const_result_iterator &i) const

bool	operator< (const const_result_iterator &i) const

bool	operator<= (const const_result_iterator &i) const

bool	operator> (const const_result_iterator &i) const

bool	operator>= (const const_result_iterator &i) const

Public Member Functions inherited from pqxx::row
	row ()=default

	row (result r, size_t i) noexcept

	~row () noexcept=default

const_iterator	begin () const noexcept

const_iterator	cbegin () const noexcept

const_iterator	end () const noexcept

const_iterator	cend () const noexcept

size_type	size () const noexcept

void	swap (row &) noexcept

size_t	rownumber () const noexcept
	Row number, assuming this is a real row and not end()/rend(). More...

size_t	num () const

row	slice (size_type Begin, size_type End) const

PQXX_PURE bool	empty () const noexcept

PQXX_PURE bool	operator== (const row &) const noexcept

bool	operator!= (const row &rhs) const noexcept

reference	front () const noexcept

reference	back () const noexcept

const_reverse_row_iterator	rbegin () const

const_reverse_row_iterator	crbegin () const

const_reverse_row_iterator	rend () const

const_reverse_row_iterator	crend () const

reference	operator[] (size_type) const noexcept

reference	operator[] (int) const noexcept

reference	operator[] (const char[]) const

reference	operator[] (const std::string &) const

reference	at (size_type) const

reference	at (int) const

reference	at (const char[]) const

reference	at (const std::string &) const

size_type	column_number (const std::string &ColName) const
	Number of given column (throws exception if it doesn't exist) More...

size_type	column_number (const char[]) const
	Number of given column (throws exception if it doesn't exist) More...

oid	column_type (size_type) const
	Type of given column. More...

oid	column_type (int ColNum) const
	Type of given column. More...

oid	column_type (const std::string &ColName) const
	Type of given column. More...

oid	column_type (const char ColName[]) const
	Type of given column. More...

oid	column_table (size_type ColNum) const
	What table did this column come from? More...

oid	column_table (int ColNum) const
	What table did this column come from? More...

oid	column_table (const std::string &ColName) const
	What table did this column come from? More...

size_type	table_column (size_type) const
	What column number in its table did this result column come from? More...

size_type	table_column (int ColNum) const
	What column number in its table did this result column come from? More...

size_type	table_column (const std::string &ColName) const
	What column number in its table did this result column come from? More...

Friends
class	pqxx::result

Arithmetic operators
const_result_iterator	operator+ (difference_type, const_result_iterator)

const_result_iterator	operator+ (difference_type) const

const_result_iterator	operator- (difference_type) const

difference_type	operator- (const_result_iterator) const

Additional Inherited Members
Protected Attributes inherited from pqxx::row
result	m_result
	Result set of which this is one row. More...

long	m_index = 0
	Row number. More...

size_type	m_begin = 0
	First column in slice. This row ignores lower-numbered columns. More...

size_type	m_end = 0
	End column in slice. This row only sees lower-numbered columns. More...

Detailed Description

Iterator for rows in a result. Use as result::const_iterator.

A result, once obtained, cannot be modified. Therefore there is no plain iterator type for result. However its const_iterator type can be used to inspect its rows without changing them.

Member Typedef Documentation

◆ difference_type

using pqxx::const_result_iterator::difference_type = result_difference_type

◆ iterator_category

using pqxx::const_result_iterator::iterator_category = std::random_access_iterator_tag

◆ pointer

using pqxx::const_result_iterator::pointer = const row *

◆ reference

using pqxx::const_result_iterator::reference = row

◆ size_type

using pqxx::const_result_iterator::size_type = result_size_type

◆ value_type

using pqxx::const_result_iterator::value_type = const row

Constructor & Destructor Documentation

◆ const_result_iterator() [1/2]

pqxx::const_result_iterator::const_result_iterator ( )

noexcept

◆ const_result_iterator() [2/2]

pqxx::const_result_iterator::const_result_iterator ( const row & t )

noexcept

Member Function Documentation

◆ operator!=()

bool pqxx::const_result_iterator::operator!= ( const const_result_iterator & i ) const

◆ operator*()

reference pqxx::const_result_iterator::operator* ( ) const

◆ operator+()

const_result_iterator pqxx::const_result_iterator::operator+ ( result::difference_type o ) const

◆ operator++() [1/2]

pqxx::const_result_iterator pqxx::const_result_iterator::operator++ ( int )

◆ operator++() [2/2]

const_result_iterator& pqxx::const_result_iterator::operator++ ( )

◆ operator+=()

const_result_iterator& pqxx::const_result_iterator::operator+= ( difference_type i )

◆ operator-() [1/2]

const_result_iterator pqxx::const_result_iterator::operator- ( result::difference_type o ) const

◆ operator-() [2/2]

result::difference_type pqxx::const_result_iterator::operator- ( const_result_iterator i ) const

References pqxx::row::num().

◆ operator--() [1/2]

pqxx::const_result_iterator pqxx::const_result_iterator::operator-- ( int )

◆ operator--() [2/2]

const_result_iterator& pqxx::const_result_iterator::operator-- ( )

◆ operator-=()

const_result_iterator& pqxx::const_result_iterator::operator-= ( difference_type i )

◆ operator->()

pointer pqxx::const_result_iterator::operator-> ( ) const

The iterator "points to" its own row, which is also itself. This allows a result to be addressed as a two-dimensional container without going through the intermediate step of dereferencing the iterator. I hope this works out to be similar to C pointer/array semantics in useful cases.

IIRC Alex Stepanov, the inventor of the STL, once remarked that having this as standard behaviour for pointers would be useful in some algorithms. So even if this makes me look foolish, I would seem to be in distinguished company.

◆ operator<()

bool pqxx::const_result_iterator::operator< ( const const_result_iterator & i ) const

◆ operator<=()

bool pqxx::const_result_iterator::operator<= ( const const_result_iterator & i ) const

◆ operator==()

bool pqxx::const_result_iterator::operator== ( const const_result_iterator & i ) const

◆ operator>()

bool pqxx::const_result_iterator::operator> ( const const_result_iterator & i ) const

◆ operator>=()

bool pqxx::const_result_iterator::operator>= ( const const_result_iterator & i ) const

References pqxx::operator+().

Friends And Related Function Documentation

◆ operator+

const_result_iterator operator+	(	result::difference_type	o,
		const_result_iterator	i
	)

friend

◆ pqxx::result

friend class pqxx::result