Re: [Boost-users] [Chrono] Negative real time

Subject: Re: [Boost-users] [Chrono] Negative real time
From: Vicente J. Botet Escriba (vicente.botet_at_[hidden])
Date: 2012-05-23 12:29:15

Le 23/05/12 09:39, Wilfried Kirschenmann a écrit :
> On Tue, May 22, 2012 at 9:41 PM, Vicente J. Botet Escriba 
> <vicente.botet_at_[hidden] <mailto:vicente.botet_at_[hidden]>> wrote:
>
>     Le 22/05/12 18:55, Wilfried Kirschenmann a écrit :
>>     Dear chrono maintainer team,
>>
>>
>>     I run boost 1.49 win32 on Windows 7 x64 with Visual studio 2010.
>>
>>     Studying the behavior of the timer, I think that the error is one
>>     of these :
>>     - process_real_cpu_clock::now() only stores the current time in a
>>     32 bit integer instead of a 64 bit integer
>
>     I don't know from where are you getting this conclusion.
>     process_real_cpu_clock is using boost::int_least64_t, as
>     representation.
>
>         typedef duration<boost::int_least64_t, nano> nanoseconds;   
>     // at least 64 bits needed
>         class BOOST_CHRONO_DECL process_real_cpu_clock {
>         public:
>             typedef nanoseconds                          duration;
>             typedef duration::rep                        rep;
>             typedef duration::period                     period;
>             typedef chrono::time_point<process_real_cpu_clock>   
>     time_point;
>             BOOST_STATIC_CONSTEXPR bool is_steady =             true;
>
>             static BOOST_CHRONO_INLINE time_point now() BOOST_NOEXCEPT;
>     #if !defined BOOST_CHRONO_DONT_PROVIDE_HYBRID_ERROR_HANDLING
>             static BOOST_CHRONO_INLINE time_point
>     now(system::error_code & ec );
>     #endif
>
>         };
>
>
> From the fact that it behaves as if there were a 32bit overflow. Which 
> is in fact the case : https://svn.boost.org/trac/boost/ticket/6361
> The problem is fixed in 1.50 and I no longer get negative times.
>
Oh my bad, I forget this issue and I was locking on the trunk. Glad to 
see that you will get a solution with 1.50 :)

Best,
Vicente