# std::basic_filebuf<CharT,Traits>::close

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< cpp‎ | io‎ | basic filebuf

std::basic_filebuf <CharT, Traits>* close(); |  |

If a put area exist (e.g. file was opened for writing), first calls overflow(Traits::eof()) to write all pending output to the file, including any unshift sequences.

If the most recently called function, out of underflow(), overflow(), seekpos(), and seekoff(), was overflow(), then calls std::codecvt::unshift(), perhaps multiple times, to determine the unshift sequence according to the imbued locale, and writes that sequence to file with overflow(Traits::eof()).

Then, closes the file as if by calling std::fclose(), regardless of whether any of the preceding calls succeeded or failed.

If any of the function calls made, including the call to std::fclose(), fails, returns a null pointer. If any of the function calls made throws an exception, the exception is caught and rethrown after calling std::fclose(). If the file is already closed, returns a null pointer right away.

In any case, updates the private member variable that is accessed by is_open().

### Parameters

(none)

### Return value

this on success, a null pointer on failure.

### Notes

`close()` is typically called through the destructor of std::basic_filebuf (which, in turn, is typically called by the destructor of std::basic_fstream.

### Example

| This section is incomplete Reason: no example

### See also

is_open | checks if the associated file is open (public member function)
(destructor) [virtual] | destructs a basic_filebuf object and closes the file if it is open (virtual public member function)

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