std::ostreambuf_iterator<CharT,Traits>::ostreambuf_iterator

 

C++

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Feature test macros (C++20)

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Concepts library (C++20)

Metaprogramming library (C++11)

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Ranges library (C++20)

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Symbols index

External libraries

 

Iterator library

Iterator concepts
indirectly_readable (C++20) indirectly_writable (C++20) weakly_incrementable (C++20) incrementable (C++20) is-integer-like is-signed-integer-like (C++20)(C++20)	sentinel_for (C++20) sized_sentinel_for (C++20) input_iterator (C++20) output_iterator (C++20) input_or_output_iterator (C++20)	forward_iterator (C++20) bidirectional_iterator (C++20) random_access_iterator (C++20) contiguous_iterator (C++20)
Iterator primitives
input_iterator_tagoutput_iterator_tagforward_iterator_tagbidirectional_iterator_tagrandom_access_iterator_tagcontiguous_iterator_tag (C++20)	iter_value_titer_difference_titer_reference_titer_const_reference_titer_rvalue_reference_titer_common_reference_t (C++20)(C++20)(C++20)(C++23)(C++20)(C++20)	iterator (deprecated in C++17) iterator_traits incrementable_traits (C++20) indirectly_readable_traits (C++20)
Algorithm concepts and utilities
Indirect callable concepts
indirectly_unary_invocableindirectly_regular_unary_invocable (C++20)(C++20)	indirect_unary_predicate (C++20) indirect_binary_predicate (C++20)	indirect_equivalence_relation (C++20) indirect_strict_weak_order (C++20)
Common algorithm requirements
indirectly_movable (C++20) indirectly_movable_storable (C++20) indirectly_copyable (C++20)	indirectly_copyable_storable (C++20)   indirectly_swappable (C++20) indirectly_comparable (C++20)	permutable (C++20) mergeable (C++20) sortable (C++20)
Utilities
indirect_result_t (C++20)	projected (C++20)	projected_value_t (C++26)
Iterator adaptors
reverse_iterator make_reverse_iterator (C++14) move_iterator (C++11) make_move_iterator (C++11) default_sentinel_tdefault_sentinel (C++20)(C++20) unreachable_sentinel_tunreachable_sentinel (C++20)(C++20)	front_insert_iterator back_insert_iterator inserter insert_iterator front_inserter back_inserter move_sentinel (C++20)	common_iterator (C++20) counted_iterator (C++20) basic_const_iterator (C++23) const_iterator (C++23) const_sentinel (C++23) make_const_iterator (C++23) make_const_sentinel (C++23)
Stream iterators istream_iterator    ostream_iterator istreambuf_iterator ostreambuf_iterator	Iterator customization points ranges::iter_move (C++20) ranges::iter_swap (C++20)
Iterator operations advance distance prev (C++11)   next (C++11) ranges::advance (C++20) ranges::distance (C++20) ranges::prev (C++20) ranges::next (C++20)	Range access begincbegin (C++11)(C++14) rbegincrbegin (C++14)(C++14)   endcend (C++11)(C++14) rendcrend (C++14)(C++14)   sizessize (C++17)(C++20) empty (C++17) data (C++17)

 

std::ostreambuf_iterator

Member functions

ostreambuf_iterator::ostreambuf_iterator

ostreambuf_iterator::operator=

ostreambuf_iterator::operator*

ostreambuf_iterator::operator++ostreambuf_iterator::operator++(int)

ostreambuf_iterator::failed

 

	(1)
ostreambuf_iterator( streambuf_type* buffer ) throw();			(until C++11)
ostreambuf_iterator( streambuf_type* buffer ) noexcept;			(since C++11)
		(2)
ostreambuf_iterator( ostream_type& stream ) throw();				(until C++11)
ostreambuf_iterator( ostream_type& stream ) noexcept;				(since C++11)

1) Constructs the iterator with the private streambuf_type* member set to buffer and the failed() flag set to false. The behavior is undefined if buffer is a null pointer.

2) Same as ostreambuf_iterator(stream.rdbuf()).

Parameters

stream	-	the output stream whose rdbuf() will be accessed by this iterator
buffer	-	the output stream buffer to be accessed by this iterator

Example

Run this code

#include <fstream>
#include <iostream>
#include <iterator>
 
int main()
{
    const char* file = "test.txt";
    {
        std::basic_filebuf<char> f;
        f.open(file, std::ios::out);
        std::ostreambuf_iterator<char> out1(&f);
        *out1 = 'a'; // writes to file via iterator
    }
 
    // read back from the file
    char a;
    std::cout << ((std::ifstream{file} >> a), a) << std::endl;
 
    std::ostreambuf_iterator<wchar_t> out2{std::wcout};
    *out2 = L'b';
}

Output:

a
b

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR	Applied to	Behavior as published	Correct behavior
LWG 112	C++98	the requirement "the argument cannot be null" was applied to overload (2)	applies to overload (1) instead
P2325R3	C++20	default constructor was provided as C++20 iterators must be default_initializable	removed along with the requirement