[Boost-bugs] [Boost C++ Libraries] #12170: boost::multiprecision::export_bits throws on a negative cpp_int number

Subject: [Boost-bugs] [Boost C++ Libraries] #12170: boost::multiprecision::export_bits throws on a negative cpp_int number
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2016-05-02 08:54:11

#12170: boost::multiprecision::export_bits throws on a negative cpp_int number
-------------------------------------------------+-------------------------
 Reporter:  Tassilo Glander <tassilo.glander@…>  |      Owner:  johnmaddock
     Type:  Bugs                                 |     Status:  new
Milestone:  To Be Determined                     |  Component:
  Version:  Boost 1.60.0                         |  multiprecision
 Keywords:  export_bits cpp_int                  |   Severity:  Problem
-------------------------------------------------+-------------------------
 When calling export_bits on a negative boost::multiprecision number based
 on cpp_int, an exception is thrown from the internal method msb ("testing
 individual bits in negative values is not supported").

 boost::multiprecision::checked_int128_t i (-1); // use negative number
 std::vector<unsigned char> v;
 export_bits(i, std::back_inserter(v), 8);  // throws

 export_bits is designed to be used for data exchange, so must export valid
 data.

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Ticket URL: <https://svn.boost.org/trac/boost/ticket/12170>
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