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Subject: Re: [boost] [filesystem][v3] Class path codecvt argument now available for appropriate functions
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2010-06-24 12:31:02

Beman Dawes wrote:
> The initial V3 implementation, like V2, could alter the codecvt facet
> used for conversion via a static imbue() function. This has a number
> of problems, including:
> * It is, in effect, a global variable, and thus "considered harmful"
> as being prone to abuse.

Many things in the standard library can be abused. That doesn't mean it should be easy or the only way to do a thing, but there is precedent for the inclusion of abuse prone constructs.

> * It is subject to data races in multi-threaded environments.

If an application imbues a codecvt facet in main() before creating threads, is that still an issue? IOW, can it not be used safely?

> * It can be hard to use.
> * It can be hard to explain.

No comment.

> As of revision 63283 this morning, V3 class path in trunk now has an
> additional "const codecvt&" for all functions where conversion may be
> required.[snip]
> That's great, but where does that leave path::imbue? I think it should
> be deprecated. What do others think?

I'd be inclined to leave it for those that always want a single codecvt facet, but I have no horse in this race.

Rob Stewart robert.stewart_at_[hidden]
Software Engineer, Core Software using std::disclaimer;
Susquehanna International Group, LLP

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