[libstdc++] numeric_limits: round_style, round_error

[Mark Mitchell]

> Next, round_error is intimately tied to round_style.  When
> round_style is round_to_nearest, this value should be 0.5.
> While this is a function, not a constant, I think it would
> be confusing to vary at runtime when round_style doesn't.

A technical comment, which I'm not sure applies, since I didn't try to
read through all of the patches.

  If you have changed the value of *any* constant exposed by a V3
  header, you have changed the ABI.

That's beacause I can do things like:

  template <int I>
  void f() {}

  void g() { f<std::some_constant>(); }

Changing the value of the constant will change the set of templates
required by a program.

I'm not sure that anyone care.

*I* don't, for things like this; if we're fixing bugs in the library,
that's good.

However, we should point out in case somebody cares.

-- 
Mark Mitchell                mark@codesourcery.com
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