Re: [Boost-bugs] [Boost C++ Libraries] #6975: lexical_cast<double> produces different answers with 53-bit FPU precision

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #6975: lexical_cast<double> produces different answers with 53-bit FPU precision
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2012-07-24 18:12:05

#6975: lexical_cast<double> produces different answers with 53-bit FPU precision
------------------------------------------------------------+---------------
  Reporter:  Jonathan Jones <jonathan.jones@…>              |       Owner:  apolukhin   
      Type:  Support Requests                               |      Status:  assigned    
 Milestone:  To Be Determined                               |   Component:  lexical_cast
   Version:  Boost 1.49.0                                   |    Severity:  Cosmetic    
Resolution:                                                 |    Keywords:              
------------------------------------------------------------+---------------
Changes (by apolukhin):

  * status:  new => assigned
  * type:  Bugs => Support Requests
  * severity:  Problem => Cosmetic

Comment:

 This issue won't be fixed in nearest future (it shall be fixed in ticket
 #5660)

 When casting to doubles, lexical_cast uses long doubles for getting better
 precision and assumes that long doubles precision set to 64 (default).
 But even with 53bit precision result is accurate enougth, so this bug is
 not critical.

 By the way: you shall not compare floats using == and != operatos.
 See http://www.parashift.com/c++-faq-lite/floating-point-arith.html

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/6975#comment:1>
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