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Re: wrong description of effect 1 of basic_istream:: ignore

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Am 25.09.2011 06:46, schrieb Krzysztof Żelechowski:
>  Daniel Krügler wrote:
>
>>    Am 11.09.2011 18:12, schrieb Krzysztof Żelechowski:
>>>     [istream.unformatted] in N3242 currently has the following to say about
>>>     [the
>>>     semantics of basic_istream:: ignore:
>>>
>>>          Characters are extracted until any of the following occurs:
>>>     — if n != numeric_limits<streamsize>::max() (18.3.2), n characters are
>>>     extracted
>>>
>>>     This statement, apart from being slightly ungrammatical, indicates that
>>>     if
>>>     (n == numeric_limits<       streamsize>:: max ()), the method returns
>>>     without extracting any characters.
>>
>>    I tend to disagree in regard to your argumentation chain. If we have the
>>    situation "n == numeric_limits<streamsize>::max()", the first bullet can
>>    never be entered (because it simply does not occur) but the initiating
>>    assertion ("Characters are extracted until any of the following occurs")
>>    still holds. Therefore, in this case the stop condition for character
>>    extraction can only be one of bullet two or bullet three.
>
>  The description intends to describe the observable behaviour of an
>  implementation in terms of logical assertions.  Logical assertions are not
>  "bullets" that can be "entered" but need not; they are predicates that can
>  evaluate to true or false.
>
>  The description contains two predicates, either of them causes extraction to
>  terminate.  In the incriminated case, the first predicate is evaluates to
>  true because its premise is false, therefore no characters will be
>  extracted.

Yes, you are correct, I misread your interpretation. I forwarded your
issue to the library group.

Thanks&  Greetings from Bremen,

Daniel Krügler



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wrong description of effect 1 of basic_istream:: ignore Krzysztof Żelechowski<giecrilj@stegny.2a.pl> - 2011-09-11 09:12 -0700
  Re: wrong description of effect 1 of basic_istream:: ignore Daniel Krügler<daniel.kruegler@googlemail.com> - 2011-09-20 10:11 -0700
    Re: wrong description of effect 1 of basic_istream:: ignore Krzysztof Żelechowski<giecrilj@stegny.2a.pl> - 2011-09-24 21:46 -0700
      Re: wrong description of effect 1 of basic_istream:: ignore Daniel Krügler<daniel.kruegler@googlemail.com> - 2011-09-25 08:31 -0700

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