[Boost-bugs] [Boost C++ Libraries] #10188: Loses floating point precision on round trip

Subject: [Boost-bugs] [Boost C++ Libraries] #10188: Loses floating point precision on round trip
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2014-07-10 13:54:12

#10188: Loses floating point precision on round trip
----------------------------------------------+---------------------------
 Reporter:  Magne OEstlyngen <magne+boost@…>  |      Owner:  cornedbee
     Type:  Bugs                              |     Status:  new
Milestone:  To Be Determined                  |  Component:  property_tree
  Version:  Boost Development Trunk           |   Severity:  Problem
 Keywords:                                    |
----------------------------------------------+---------------------------
 ptrees stream_translator uses a precision of
 std::numeric_limits<F>::digits10 + 1 when converting floating point
 values.  This is not always enough, and a more correct value would be
 digits10+2 or max_digits10 (c++11 only). See ticket:9177 for a similar
 issue.

 The attached test produces the following output pre-patch:
 {{{
 in : -1.8312345000098765e-08
 out: -1.8312345000098762e-08
 Wrong
 }}}

 and after patch:
 {{{
 in : -1.8312345000098765e-08
 out: -1.8312345000098765e-08
 Right
 }}}

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/10188>
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