Re: [PATCH, libstdc++] Uniform container erasure for c++20.

[Ed Smith-Rowland <3dw4rd at verizon dot net>]

On 11/26/18 6:18 AM, Jonathan Wakely wrote:
> On 24/11/18 13:54 -0500, Ed Smith-Rowland wrote:
> > All,
> >
> > I's very late but uniform container erasure is, I think, the last 
> > little tidbit to graduate from fundamentals/v2 to std at the last 
> > meeting.  I think it would be a shame not to nudge this into gcc-9.  
> > The routines are very short so I just copied them. Ditto the 
> > testcases (with adjustments).  The node erasure tool was moved from 
> > experimental to std/bits and adjustments made to affected *set/*map 
> > headers.
> >
> > The experimental code has been in our tree since 2015.
> >
> > This builds and tests clean on x86_64-linux.
>
> OK for trunk as it only touches experimental C++2a and TS material.
> Thanks.
>
> I pointed out to the committee that the erase_if functions added to
> C++20 completely overlook P0646R1 "Improving the Return Value of
> Erase-Like Algorithms" and so fail to preserve the useful information
> returned by the members of the linked list containers.
Is *this* what you has in mind for this?  I basically return the number 
of erased items for all the things.
> I expect that to get fixed as a defect. If you have time and
> motivation, I think we should make that change proactively in
> libstdc++. The Library Fundamentals versions can continue to return
> void, but the ones in namespace std can return the number of elements
> removed

Ed

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