[Boost-bugs] [Boost C++ Libraries] #6959: call of abs is ambiguous

Subject: [Boost-bugs] [Boost C++ Libraries] #6959: call of abs is ambiguous
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2012-06-02 19:13:47

#6959: call of abs is ambiguous
------------------------------------------------------+---------------------
 Reporter:  Niklas Angare <li51ckf02@…>               |       Owner:  anthonyw
     Type:  Patches                                   |      Status:  new     
Milestone:  To Be Determined                          |   Component:  thread  
  Version:  Boost 1.49.0                              |    Severity:  Problem 
 Keywords:                                            |  
------------------------------------------------------+---------------------
 The regression tests this_thread!__sleep_for_p* and
 this_thread!__sleep_until_p* fail to compile on QNX 6.5.0:
 {{{
 sleep_for_pass.cpp:38: error: call of overloaded 'abs(long int)' is
 ambiguous
 }}}

 Here's the troublesome line:
 {{{
 BOOST_TEST(std::abs(static_cast<long>(ns.count())) <
 (err+boost::chrono::milliseconds(1000)).count());
 }}}

 I'm thinking that it might be a compiler bug but either way it should be
 easy to work around.

 I guess the static_cast is a work-around for the fact that C++03 doesn't
 have abs(long long). I'm attaching a patch with a more reliable solution,
 with no risk of 32-bit overflow:
 {{{
 BOOST_TEST(std::max(ns, -ns) < (err+boost::chrono::milliseconds(1000)));
 }}}


 These also work but have the overflow problem:
 {{{
 BOOST_TEST(std::abs(static_cast<int>(ns.count())) <
 (err+boost::chrono::milliseconds(1000)).count());
 }}}

 {{{
 BOOST_TEST(std::labs(static_cast<long>(ns.count())) <
 (err+boost::chrono::milliseconds(1000)).count());
 }}}

 As a side note; one of the tests end with ''return
 boost::report_errors()'' while the other one doesn't. Bug?

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/6959>
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