Re: How large is the stream buffer?

From:
James Kanze <james.kanze@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Tue, 15 Jul 2008 06:15:20 -0700 (PDT)
Message-ID:
<2e67959e-6e26-4e0f-a518-e69992a57226@l64g2000hse.googlegroups.com>
On Jul 15, 2:28 pm, Lambda <stephenh...@gmail.com> wrote:

As I know, when I use ifstream and ofstream to read and write file,
it will use a stream buffer internally.
How large is the stream buffer?


About so big.

It depends on the implementation, and will often be optimized
for the system you're running under.

If I want to write a large file, need I define a stream buffer
myself?


No.

In what situation, user-defined stream buffer is useful?


Any time the non-standard ones aren't sufficient. The most
frequent use is probably filtering streambuf's; it's hard to
imagine an application that doesn't use at least one (if only
for log dispatching). Non-filtering user written streambuf's
are used to interface with sockets, pipes, raw memory, or just
about anything else besides ordinary files and std::strings.

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