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

From cppreference.com
< cpp‎ | iterator‎ | ostreambuf iterator

| (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

Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/iterator/ostreambuf_iterator/ostreambuf_iterator&oldid=142384"