Re: [boost] [afio] Formal review of Boost.AFIO

Subject: Re: [boost] [afio] Formal review of Boost.AFIO
From: Thomas Heller (thom.heller_at_[hidden])
Date: 2015-08-31 10:57:04

On 08/31/2015 04:13 PM, Niall Douglas wrote:
> On 30 Aug 2015 at 22:47, Thomas Heller wrote:
> 
>>> No, this stuff is at the core of where we are diverging in approach
>>> and why the AFIO API is so displeasing to you.
>>>
>>> Where I am coming from is this:
>>>
>>> "If the cost of defaulting to guaranteed memory safety to the end
>>> user is less than 0.5% overhead, I will default to guaranteed memory
>>> safety."
>>
>> Where did you get this number from?
> 
> The benchmarks I ran before deciding on whether enforcing shared_ptr 
> on handle was an acceptable overhead.
> 
> You've got to understand Thomas you and your fellow HPC colleagues 
> are attacking AFIO's "overhead" without having run any benchmarks. 
> You're claiming all this poor performance and high overhead stuff 
> having absolutely no idea of performance on the ground. As I much as 
> I appreciate where you think you're coming from, the benchmarks I ran 
> before deciding on a shared_ptr on every handle said it was an 
> inconsequential overhead. That's why I chose that design.

Now now, I merely asked where you got the numbers from. Where I come from?
>From a purely API design, aka semantics point of view. You are the one
talking about high performance and stuff, but fail to deliver.

<snip>

> 
>> Why isn't it possible that consumers of AFIO implement all those ABI
>> stability stuff? 
> 
> You don't appear to understand well how ABI stable C++ is designed. 
> It requires imposing costs on everybody. Look at the PIMPL idiom.

The PIMPL idiom has absolutely *nothing* to do with ABI stability.