Re: [boost] [Container] Provide more guarantees for flat_multimap

Subject: Re: [boost] [Container] Provide more guarantees for flat_multimap
From: Niall Douglas (s_sourceforge_at_[hidden])
Date: 2014-08-21 08:29:22

On 19 Aug 2014 at 15:27, Rob Stewart wrote:

> >Pre-C++11 I would agree. However availability of variadic args makes 
> >putting tags at the end harder than at the start. For me personally 
> >in my own code, I would prefer all tags to go at the front rather 
> >than some at the start and some at the end.
> >
> >Ok, I'm being lazy, but it saves productivity in having to write 
> >Args&&... filters just to put tags at the end.
> 
> I put non-const reference parameters (for "out" arguments) first because
> of defaults, so it's the same idea. Putting the tag first is a bit
> jarring at first, but I like your argument. 

I ended up backing out the tagged noalloc insert() dispatch, and now 
it's plain old insert_noalloc().

Why? Because if you tag dispatch insert(node_ptr), then you start 
thinking you really ought to add noalloc overloads for all the 
modifying functions. Which maybe you should, but then one is 
deviating quite far from what I originally intended which is merely 
that some functional noalloc mechanism should be available for those 
rare users wanting such a thing, not that it is being endorsed for 
all use cases and raising my maintenance burden.

Anyway, for those interested, my concurrent_unordered_map is now 90% 
functionally tested and many bugs have been found and fixed. I move 
onto exception safety unit testing next, and for which I shall need 
to write an allocator which can be made to throw at exactly the right 
point within the map's implementation. I expect that will take 
another week at least as this Saturday my day is full of other tasks.

WiP code lives at https://github.com/ned14/boost.spinlock.

Niall

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