Re: [Boost-bugs] [Boost C++ Libraries] #11756: boost.Test: non standards compliant use of FE_* macros (unable to compile boost test library on FPU-less arches)

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #11756: boost.Test: non standards compliant use of FE_* macros (unable to compile boost test library on FPU-less arches)
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2017-03-09 12:20:25

#11756: boost.Test: non standards compliant use of FE_* macros (unable to compile
boost test library on FPU-less arches)
----------------------------------+------------------------
  Reporter:  bartosz.krasinski@…  |      Owner:  renficiaud
      Type:  Patches              |     Status:  reopened
 Milestone:  Boost 1.64.0         |  Component:  test
   Version:  Boost 1.59.0         |   Severity:  Problem
Resolution:                       |   Keywords:
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Comment (by renficiaud):

 Ok, now I think I understood the problem:

 * the ```feenableexcept/fedisableexcept``` are not standard, those are
 ``GLIBC`` extensions
 * having fenv does not ensure that those 2 functions are in there, for
 having those function, we should be ensured that we are indeed compiling
 with GLIBC
 * however, for anything outside this and SEH based extensions, there is no
 easy way to mask floating point exceptions

 So, I suggest the following:

 * The macro indicating that the floating point exception settings is
 supported becomes ```BOOST_TEST_FPE_SUPPORT_WITH_GLIBC_EXTENSIONS__``` and
 is defined like this:

 {{{
 #if defined(BOOST_SEH_BASED_SIGNAL_HANDLING) && !defined(UNDER_CE)
   //! Indicates tha the floating point exception handling is supported
   //! through SEH
   #define BOOST_TEST_FPE_SUPPORT_WITH_SEH__
 #elif !defined(BOOST_SEH_BASED_SIGNAL_HANDLING) && !defined(UNDER_CE)
   #if !defined(BOOST_NO_FENV_H) && !defined(BOOST_CLANG) && \
       (defined(__GLIBC__) && defined(__USE_GNU))
   //! Indicates that floating point exception handling is supported for
 the
   //! non SEH version of it, for the GLIBC extensions only
   #define BOOST_TEST_FPE_SUPPORT_WITH_GLIBC_EXTENSIONS__
   #endif
 #endif

 }}}

 * the branch taking the ```feenableexcept/fedisableexcept``` is guarded by
 this macro
 * the branch taking the SEH extension is not affected
 * all the rest is falls back to the "unsupported" branch (returning
 ```BOOST_FPE_OFF/BOOST_FPE_INV```). In particular, I do not see how to
 support **3.a** from your comment.

 Does this sound correct?

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/11756#comment:41>
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