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From: Daryle Walker (dwalker07_at_[hidden])
Date: 2003-06-04 18:23:18

On Monday, June 2, 2003, at 12:21 PM, Ed Brey wrote:

> Daryle Walker wrote:
>> I fixed up the I/O library I had reviewed a few months ago. It was
>> some little things last week, but some big documentation and testing
>> this week. It's in the sandbox if you want to try it out.
> Looking at today's version in the sandbox, I still see the following
> high-level questions from the formal review looming without clear
> answers.

Didn't we go over these questions during the main review period? Also,
I hope the new stuff in the documentation provides explanations.

> * Stream-buffer-wrapping Streams motivation: Why would someone want an
> internal buffer (versus independent buffers as used by standard
> streams)? (Example, please.)

The basic stream (template) classes support attaching a stream buffer
after the stream is constructed. However, that technique is not used
for the two example stream categories in the standard (files and
strings). The standard example streams act if they contain their
appropriate stream buffer and make the proper connections to it. The
templates I provide just aid in an user simulating that effect.

I've been considering contributing several stream categories to Boost.
Unless I just offer the custom stream buffers by themselves and make
the user do the stream allocations and connections, I would have to
supply matching custom stream classes with manual stream buffer
containment and connection. Instead of writing lots of custom code, I
realized that I could have the computer help with the repetition, and
that's where the idea of the stream-buffer-wrapping streams came from.

> * Array-Based Streams motivation: When is the class more suitable than
> std::stringstream? (Example, please.)

You generally wouldn't use these streams over string-based streams.
The only advantage is that the storage for the characters is
non-dynamic. That could help in memory-restrained environments.

> * newl differs from '\n' only in that newl doesn't perform background
> formatting. Presumably one would choose to use newl to avoid the
> formatting. What is undesirable about '\n' being formatted?

Formatted printing calls usually reset the width attribute and go
through the locale mechanism. Unformatted calls don't do either.

There is also the argument that boost::newl looks better because it's
object based, instead of using a raw '\n'. People wanting an object
based style now use std::endl, which carries the extra flush. That
flush usually isn't wanted and adds an extra step.

Finally, the standard has a manipulator for flushing (std::flush) and
one for a line-break & flush (std::endl). This manipulator fills the
hole; something that just does a line break.

> There are lower-level issues remaining, too, but these are more
> appropriate to address after the high-level issues are resolved.


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