[Boost-bugs] [Boost C++ Libraries] #12176: Chrono without linking to Boost.System

Subject: [Boost-bugs] [Boost C++ Libraries] #12176: Chrono without linking to Boost.System
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2016-05-04 13:06:01

#12176: Chrono without linking to Boost.System
------------------------------+---------------------
 Reporter:  eldiener          |      Owner:
     Type:  Bugs              |     Status:  new
Milestone:  To Be Determined  |  Component:  None
  Version:  Boost 1.61.0      |   Severity:  Problem
 Keywords:                    |
------------------------------+---------------------
 In the chrono docs we have:

 {{{
 How to Build Boost.Chrono as a Header Only Library?

 When BOOST_CHRONO_HEADER_ONLY is defined the lib is header-only.

 If in addition BOOST_USE_WINDOWS_H is defined <windows.h> is included,
 otherwise files in boost/detail/win are used to reduce the impact of
 including <windows.h>.

 However, you will either need to define
 BOOST_CHRONO_DONT_PROVIDE_HYBRID_ERROR_HANDLING or link with Boost.System.
 }}}

 But when I followed this chrono still linked with Boost.System. Here is
 the code:


 {{{
 #define BOOST_CHRONO_HEADER_ONLY
 #define BOOST_CHRONO_DONT_PROVIDE_HYBRID_ERROR_HANDLING
 // #define BOOST_SYSTEM_NO_DEPRECATED

 #include <iostream>
 #include <boost/chrono.hpp>
 #include <boost/ratio.hpp>

 int main()
   {
   typedef boost::chrono::duration<int, boost::ratio<1, 100000000> >
 shakes;
   typedef boost::chrono::duration<int, boost::centi> jiffies;
   typedef boost::chrono::duration<float, boost::ratio<12096,10000> >
 microfortnights;
   typedef boost::chrono::duration<float, boost::ratio<3155,1000> >
 nanocenturies;
   boost::chrono::seconds sec(1);
   std::cout << "1 second is:\n";
   std::cout << boost::chrono::duration_cast<shakes>(sec).count()
               << " shakes\n";
   std::cout << boost::chrono::duration_cast<jiffies>(sec).count()
               << " jiffies\n";
   std::cout << microfortnights(sec).count() << " microfortnights\n";
   std::cout << nanocenturies(sec).count() << " nanocenturies\n";
   return 0;
   }
 }}}

 The link error message is:


 {{{
 gcc.link C:\Programming\VersionControl\modular-
 boost\build\boost\bin.v2\libs\cxx_dual\test\test_chrono_boost.test\gcc-
 mingw-5.3\debug\test_chrono_boost.exe
 C:\Programming\VersionControl\modular-
 boost\build\boost\bin.v2\libs\cxx_dual\test\test_chrono_boost.test\gcc-
 mingw-5.3\debug\test_chrono_boost.o: In function
 `_static_initialization_and_destruction_0':
 E:\Programming\VersionControl\modular-
 boost\libs\cxx_dual\test/../../../boost/system/error_code.hpp:221:
 undefined reference to `boost::system::generic_category()'
 E:\Programming\VersionControl\modular-
 boost\libs\cxx_dual\test/../../../boost/system/error_code.hpp:222:
 undefined reference to `boost::system::generic_category()'
 E:\Programming\VersionControl\modular-
 boost\libs\cxx_dual\test/../../../boost/system/error_code.hpp:223:
 undefined reference to `boost::system::system_category()'
 collect2.exe: error: ld returned 1 exit status
 }}}

 If I uncomment the line:

 {{{
 // #define BOOST_SYSTEM_NO_DEPRECATED
 }}}

 then chrono links without requiring Boost.System.

 Maybe this bug is one of documentation and the documentation should be
 changed to specify that BOOST_SYSTEM_NO_DEPRECATED must also be defined in
 order to remove the chrono dependency on Boost.System.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/12176>
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