id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc
11201,setting boost::posix_time::time_facet has no effect on boost::log sinks,Georg Sauthoff <mail@…>,Andrey Semashev,"How to reproduce:


{{{
#include <boost/date_time/posix_time/posix_time.hpp>

#include <boost/log/trivial.hpp>
#include <boost/log/core.hpp>
#include <boost/log/expressions.hpp>

#include <boost/log/utility/setup/console.hpp>
#include <boost/log/attributes.hpp>

#include <locale>

int main(int argc, char **argv)
{
  auto clog = boost::log::add_console_log();
  clog->set_formatter(
        boost::log::expressions::stream
          << ""["" << boost::log::trivial::severity << ""] ""
          << boost::log::expressions::smessage
      );

  const char date_format[] = ""%Y-%m-%d %H:%M:%S"";
  // does not work
  clog->imbue(std::locale(clog->getloc(),
    new boost::posix_time::time_facet(date_format)
        ));

  boost::posix_time::ptime dt(
      boost::gregorian::date(2015, 1, 1),
      boost::posix_time::time_duration(8, 48, 0)
      );
  BOOST_LOG_TRIVIAL(info) << dt;
  BOOST_LOG_TRIVIAL(info) << dt;

  return 0;
}
}}}

Expected output:

{{{
$ ./test_log_datetime
[info] 2015-01-01 08:48:00
[info] 2015-01-01 08:48:00
}}}

Actual output:

{{{
$ ./test_log_datetime
[info] 2015-Jan-01 08:48:00
[info] 2015-Jan-01 08:48:00
}}}


When stepping through the code I observe that the output operator in {{{boost/posix_time/posix_time_io.hpp}}}

{{{
  operator<<(std::basic_ostream<CharT, TraitsT>& os,
             const boost::posix_time::time_period& p) {
    boost::io::ios_flags_saver iflags(os);
    typedef boost::date_time::time_facet<ptime, CharT> custom_ptime_facet;
    std::ostreambuf_iterator<CharT> oitr(os);
    if (std::has_facet<custom_ptime_facet>(os.getloc())) {
      std::use_facet<custom_ptime_facet>(os.getloc()).put(oitr, os, os.fill(), p);
    }
    else {
      //instantiate a custom facet for dealing with periods since the user
      //has not put one in the stream so far.  This is for efficiency 
      //since we would always need to reconstruct for every time period
      //if the local did not already exist.  Of course this will be overridden
      //if the user imbues as some later point.
      custom_ptime_facet* f = new custom_ptime_facet();
      std::locale l = std::locale(os.getloc(), f);
      os.imbue(l);
      f->put(oitr, os, os.fill(), p);
    }
    return os;
}}}

is executed 2 times - as expected - but the condition is both times false. Expected behaviour: both times true, or at least: first time false and 2nd time true.


Even when not trying to set a custom facet:

{{{
#include <boost/date_time/posix_time/posix_time.hpp>

#include <boost/log/trivial.hpp>


int main(int argc, char **argv)
{
  boost::posix_time::ptime dt(
      boost::gregorian::date(2015, 1, 1),
      boost::posix_time::time_duration(8, 48, 0)
      );
  BOOST_LOG_TRIVIAL(info) << dt;
  BOOST_LOG_TRIVIAL(info) << dt;

  return 0;
}
}}}

the debugger shows that the default facet is instantiated 2 times in {{{boost/posix_time/posix_time_io.hpp}}} (i.e. condition is both times false).


When not using Boost Log, setting the facet works as expected:

{{{
#include <boost/date_time/posix_time/posix_time.hpp>

#include <iostream>
#include <locale>

int main(int argc, char **argv)
{
  const char date_format[] = ""%Y-%m-%d %H:%M:%S"";
  std::clog.imbue(std::locale(std::clog.getloc(),
      new boost::posix_time::time_facet(date_format)
          ));

  boost::posix_time::ptime dt(
      boost::gregorian::date(2015, 1, 1),
      boost::posix_time::time_duration(8, 48, 0)
      );
  std::clog << dt << '\n';
  std::clog << dt << '\n';

  return 0;
}
}}}

Output:

{{{
2015-01-01 08:48:00
2015-01-01 08:48:00
}}}

The debugger shows that the condition in the output operator in {{{boost/posix_time/posix_time_io.hpp}}} is both times true, as expected.

Also as expected, when commenting out the {{{clog.imbue()}}} call, the condition is the first time false, and the second time true.",Bugs,closed,To Be Determined,log,Boost Development Trunk,Problem,invalid,,