C++ Stream buffer behavior

Asked Jul 02 '17 at 23:53

Active Jul 02 '17 at 23:53

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Does c++ automatically flush the ofstream when it is full? For example:

std::ofstream OFile;
OFile.open("file.txt");
for (int i = 0; i < N; ++i) { 
OFile << a << " " << b << " " << c << '\n';}
OFile.close()

Here, I did not use any manipulator to flush the buffer. Is it possible that the output file is written incompeletly when the stream is full? Or will that be automatically flushed when the stream is full?

Thanks.

asked Jul 02 '17 at 23:53

Eman

If you didn't manually flush, the stream will automatically flush when full. – David G Jul 02 '17 at 23:55
Thanks for the response. – Eman Jul 03 '17 at 01:20
What do you mean by *full*? Do you mean that the file that is streamed to achieves the maximum size supported by the filesystem? – eerorika Jul 03 '17 at 01:25
The buffer will be flushed whenever it gets full and when the file is closed. – Pete Becker Jul 03 '17 at 01:50
Incidentally, instead of creating an `std::ofstream` object and then opening it you can open it with the constructor. And you don't need to call `close()` -- the destructor will do that. – Pete Becker Jul 03 '17 at 01:52

C++ Stream buffer behavior

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