Re: [boost] [function] function wrapping and exception safety recap

Subject: Re: [boost] [function] function wrapping and exception safety recap
From: Emil Dotchevski (emil_at_[hidden])
Date: 2010-10-11 14:05:08

On Mon, Oct 11, 2010 at 10:45 AM, Daniel Walker
<daniel.j.walker_at_[hidden]> wrote:
> On Mon, Oct 11, 2010 at 2:49 AM, Nevin Liber <nevin_at_[hidden]> wrote:
>> On 11 October 2010 00:01, Emil Dotchevski <emil_at_[hidden]> wrote:
>>> On Sat, Oct 9, 2010 at 12:38 PM, Daniel Walker
>>> <daniel.j.walker_at_[hidden]> wrote:
>>>> Finally, there have been suggestions to alter boost::function's
>>>> exception safety guarantee directly through either policies or
>>>> constructor options.
>>>
>>> We used to have an Allocator parameter to the boost::function template
>>> and it was removed (just in time for this change to also be reflected
>>> in C++0x) to reduce coupling.
>>
>> So what exactly is the proposed behavior if the function object cannot
>> fit in the small object optimization space of unsafe_function and the
>> allocation fails?
>
> As proposed, unsafe_function has the same semantics as boost::function
> with one (and only one) exception: the behavior of operator() is
> undefined when it has no target.

If that was the only motivation, you could just disable exception
handling, and then define:

namespace boost
{
  void throw_exception( std::exception const & )
  {
    assert(0);
  }
}

Emil Dotchevski
Reverge Studios, Inc.
http://www.revergestudios.com/reblog/index.php?n=ReCode