Re: [boost] [locale] Review part 1: headers

Subject: Re: [boost] [locale] Review part 1: headers
From: Mathias Gaunard (mathias.gaunard_at_[hidden])
Date: 2011-04-09 16:47:04

On 09/04/2011 20:29, Artyom wrote:
>
>>>
>>>> line 646: Normally it's undefined behavior  to
>>>>     dereference an iterator like this.  I  would
>>>>     prefer an assert to throwing an  exception.
>>>>
>>>
>>> The point is that these locations are  valid
>>> positions just you can't call operator*.
>>>
>>> I think  it is better behavior because it
>>> is quite easy to make a mistake with  this.
>>>
>>> (From my experience with this)
>>>
>>
>> Of course,  it's a good thing to detect
>> the error.  The thing is that an  exception
>> means that you unwind the stack, possibly
>> handling the exception  at a higher level.
>> That's normally not the correct response
>> for a  programming error.
>>
>
> It is similar to std::vector's at()...
>
> Maybe, in any case I had found exception helpful,
> especially in situation when you don't a error in some part
> to shutdown entire process.
>
> Defensive but forgiving programming.

Definitely a no-no.
Dereferencing an invalid iterator is a programming error, not an 
exceptional situation.

The thing to use is an assertion.

When your code is statically wrong, the compiler refuses to generate a 
binary. Likewise, when your code is dynamically wrong, it just terminates.

Fix your code such that such situations may *never* happen. An exception 
is something that *could* happen, even in bug-free software, like a 
failure to perform an operation due to lack of the necessary resources.