[patch] Implement ISO/IEC TS 18822 C++ File system TS

[Jonathan Wakely]

On 01/05/15 20:38 +0100, Jonathan Wakely wrote:
>On 01/05/15 21:28 +0200, Daniel Krügler wrote:
>>But if I read your implementation of path::compare(const path& p)
>>correctly it *also* may allocate memory by copying _M_pathname into a
>>_Cmpt object.
>
>Yes, I agree that there's a bug here that could cause it to
>std::terminate.
>
>>I was wondering whether for this comparison there exists
>>real need to *copy* _M_pathname (potentially exceeding the memory
>>limits). Wouldn't it be possible to define a _CmptRef type that for
>>the purpose of implementing compare(const path& p) just refers to
>>references of the _M_pathname and therefore doesn't need to allocate
>>any dynamic storage? (I should have spoken of a new type _CmptRef and
>>not of your existing _Cmpt).
>
>
>Ah, I see what you mean (I thought you were suggesting some
>improvements to _Cmpt itself ... which might be possible so I'm glad
>you made me think about it :-)
>
>I think I wrote compare() like that because it was easier, and when I
>first implemented this we had COW strings so it wouldn't throw when
>copying. That isn't true now, so I need to change it.

And here's the fix for this noexcept issue, it was very simple in the
end, thanks for the idea.

Tested powerpc64le-linux, committed to trunk.

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