[Boost-bugs] [Boost C++ Libraries] #13360: std::numeric_limits<multiprecision::float128> methods fail to compile in C++11 mode

Subject: [Boost-bugs] [Boost C++ Libraries] #13360: std::numeric_limits<multiprecision::float128> methods fail to compile in C++11 mode
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2017-12-24 12:37:40

#13360: std::numeric_limits<multiprecision::float128> methods fail to compile in
C++11 mode
------------------------------+----------------------------
 Reporter:  b7.10110111@…     |      Owner:  John Maddock
     Type:  Bugs              |     Status:  new
Milestone:  To Be Determined  |  Component:  multiprecision
  Version:  Boost 1.66.0      |   Severity:  Regression
 Keywords:                    |
------------------------------+----------------------------
 The following code compiles fine in C++03 mode, but fails in C++11 mode.
 This happens in boost 1.66.0, but didn't happen in 1.63.0.

 {{{
 #include <boost/multiprecision/float128.hpp>
 int main()
 {
     std::numeric_limits<boost::multiprecision::float128>::min();
 }
 }}}

 Similar problem with some other methods — those which return without
 explicit construction of {{{number_type}}}.

 I'm compiling with g++ using the following command line:

 {{{
 g++ -std=c++11 boost-test.cpp -o boost-test -fext-numeric-literals
 -lquadmath
 }}}

 The compiler prints the following error:

 {{{
 In file included from boost-test.cpp:1:0:
 /usr/include/boost/multiprecision/float128.hpp: In instantiation of
 ‘static
 std::numeric_limits<boost::multiprecision::number<boost::multiprecision::backends::float128_backend,
 ExpressionTemplates> >::number_type
 std::numeric_limits<boost::multiprecision::number<boost::multiprecision::backends::float128_backend,
 ExpressionTemplates> >::min() [with
 boost::multiprecision::expression_template_option ExpressionTemplates =
 (boost::multiprecision::expression_template_option)0u;
 std::numeric_limits<boost::multiprecision::number<boost::multiprecision::backends::float128_backend,
 ExpressionTemplates> >::number_type =
 boost::multiprecision::number<boost::multiprecision::backends::float128_backend,
 (boost::multiprecision::expression_template_option)0u>]’:
 boost-test.cpp:4:59:   required from here
 /usr/include/boost/multiprecision/float128.hpp:645:55: error: could not
 convert ‘3.3621031431120935062626778173217526e-4932’ from ‘__float128’ to
 ‘std::numeric_limits<boost::multiprecision::number<boost::multiprecision::backends::float128_backend,
 (boost::multiprecision::expression_template_option)0u> >::number_type {aka
 boost::multiprecision::number<boost::multiprecision::backends::float128_backend,
 (boost::multiprecision::expression_template_option)0u>}’
     static number_type (min)() BOOST_NOEXCEPT { return 3
 .36210314311209350626267781732175260e-4932Q; }
                                                        ^
 }}}

-- 
Ticket URL: <https://svn.boost.org/trac10/boost/ticket/13360>
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