Re: [Boost-bugs] [Boost C++ Libraries] #6571: lexical_case<float>(someString) does not recognize IEEE exceptions

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #6571: lexical_case<float>(someString) does not recognize IEEE exceptions
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2012-02-24 10:23:10

#6571: lexical_case<float>(someString) does not recognize IEEE exceptions
-----------------------------------------------------+----------------------
  Reporter:  Chromatix <mhazadmanesh2009@…>          |       Owner:  apolukhin   
      Type:  Bugs                                    |      Status:  assigned    
 Milestone:  To Be Determined                        |   Component:  lexical_cast
   Version:  Boost 1.48.0                            |    Severity:  Problem     
Resolution:                                          |    Keywords:              
-----------------------------------------------------+----------------------

Comment (by Chromatix <mhazadmanesh2009@…>):

 Oops, it seems I mixed up boost versions.

 My boost on Windows was 1.47 which is why
 `boost::lexical_cast<string>(sqrt(-1.0))` returned `-1.#IND` on Visual
 Studio (it's 2010 btw). On 1.48 it returns `-nan` and can be converted
 back to double.[[BR]]
 So a major part of this bug report doesn't make sense now. Sorry about the
 mistake here. :(

 However, the title question still makes sense about `-1.#IND`. Neither
 `nan` nor `-1.#IND` are global standards. `-nan` is the standard on *nix
 (and GCC on windows), but all Microsoft compilers (since VS5 and even
 before that I guess) represent the error value as `-1.#IND`, `1.#QNAN`,
 etc. (Simply try `cout << sqrt(-1.0)`). So I think it's essential to
 implement such a conversion: `boost::lexical_cast<double>("-1.#IND")` to
 work. Since with a Microsoft compiler one might occasionally encounter the
 `-1.#IND` and other error strings generated by conversion methods other
 than boost::lexical_cast or from external libraries.

 I also found this: http://en.wikipedia.org/wiki/NaN#Display.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/6571#comment:7>
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