The sample program below works fine, but the valgrind shows, that 520 bytes in 6 blocks are still reachable after exit.
#include <iostream>
#include <string>
#include <boost/log/common.hpp>
#include <boost/log/sources/logger.hpp>
#include <boost/log/utility/setup/file.hpp>
#include <boost/phoenix/bind/bind_member_function.hpp>
#include <boost/shared_ptr.hpp>
namespace bl = boost::log;
namespace bp = boost::phoenix;
enum class MySeverityLevel
{
panic,
alert,
critical,
error,
warning,
notice,
info,
debug
};
BOOST_LOG_ATTRIBUTE_KEYWORD(Severity, "Severity", MySeverityLevel)
BOOST_LOG_ATTRIBUTE_KEYWORD(Channel, "Channel", std::string)
class Logger
{
public:
Logger(const std::string& CH, const MySeverityLevel SEV):
m_log(bl::keywords::channel = CH), m_channel(CH), m_severityMax(SEV)
{
m_sink = bl::add_file_log
(
bl::keywords::file_name = CH + ".log",
bl::keywords::filter = bp::bind(&Logger::filter, this, Channel.or_none(), Severity.or_none())
);
}
~Logger()
{
this->terminate();
}
void terminate()
{
if (m_sink)
{
bl::core::get()->remove_sink(m_sink);
m_sink->flush();
m_sink.reset();
}
}
void panic(const std::string& S)
{
BOOST_LOG_SEV(m_log, MySeverityLevel::panic) << S;
}
void debug(const std::string& S)
{
BOOST_LOG_SEV(m_log, MySeverityLevel::debug) << S;
}
private:
using ChannelValue = bl::value_ref<std::string, tag::Channel>;
using MySeverityLevelValue = bl::value_ref<MySeverityLevel, tag::Severity>;
bool filter(const ChannelValue& CH, const MySeverityLevelValue& SEV) const
{
if (CH && SEV)
{
return (CH.get() == m_channel) && (SEV.get() <= m_severityMax);
}
else
{
return false;
}
}
bl::sources::severity_channel_logger<MySeverityLevel, std::string> m_log;
boost::shared_ptr<bl::sinks::sink> m_sink;
const std::string m_channel;
const MySeverityLevel m_severityMax;
};
int main()
{
Logger lgA("A", MySeverityLevel::error);
lgA.panic("A: Panic");
lgA.debug("A: Debug");
lgA.terminate();
}
That's the valgrind output:
hekto@ubuntu:~$ valgrind --leak-check=full --show-leak-kinds=all ./tc0013
==48934== Memcheck, a memory error detector
==48934== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==48934== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
==48934== Command: ./tc0013
==48934==
==48934==
==48934== HEAP SUMMARY:
==48934== in use at exit: 520 bytes in 6 blocks
==48934== total heap usage: 83 allocs, 77 frees, 97,276 bytes allocated
==48934==
==48934== 8 bytes in 1 blocks are still reachable in loss record 1 of 6
==48934== at 0x4C3017F: operator new(unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==48934== by 0x4E98C61: boost::log::v2_mt_posix::sources::aux::get_severity_level() (in /usr/lib/x86_64-linux-gnu/libboost_log.so.1.65.1)
==48934== by 0x11723B: boost::log::v2_mt_posix::sources::aux::severity_level<MySeverityLevel>::set_value(MySeverityLevel) (severity_feature.hpp:135)
==48934== by 0x115E74: boost::log::v2_mt_posix::record boost::log::v2_mt_posix::sources::basic_severity_logger<boost::log::v2_mt_posix::sources::basic_channel_logger<boost::log::v2_mt_posix::sources::basic_logger<char, boost::log::v2_mt_posix::sources::severity_channel_logger<MySeverityLevel, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::log::v2_mt_posix::sources::single_thread_model>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MySeverityLevel>::open_record_unlocked<boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> >(boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> const&) (severity_feature.hpp:252)
==48934== by 0x114961: boost::log::v2_mt_posix::record boost::log::v2_mt_posix::sources::basic_composite_logger<char, boost::log::v2_mt_posix::sources::severity_channel_logger<MySeverityLevel, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::log::v2_mt_posix::sources::single_thread_model, boost::log::v2_mt_posix::sources::features<boost::log::v2_mt_posix::sources::severity<MySeverityLevel>, boost::log::v2_mt_posix::sources::channel<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >::open_record<boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> >(boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> const&) (basic_logger.hpp:575)
==48934== by 0x1135A5: Logger::panic(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (tc0013.cpp:81)
==48934== by 0x11097B: main (tc0013.cpp:120)
==48934==
==48934== 8 bytes in 1 blocks are still reachable in loss record 2 of 6
==48934== at 0x4C3017F: operator new(unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==48934== by 0x4E9EF69: boost::log::v2_mt_posix::aux::this_thread::get_id() (in /usr/lib/x86_64-linux-gnu/libboost_log.so.1.65.1)
==48934== by 0x4E8BB96: boost::log::v2_mt_posix::core::open_record(boost::log::v2_mt_posix::attribute_set const&) (in /usr/lib/x86_64-linux-gnu/libboost_log.so.1.65.1)
==48934== by 0x118DEA: boost::log::v2_mt_posix::record boost::log::v2_mt_posix::sources::basic_logger<char, boost::log::v2_mt_posix::sources::severity_channel_logger<MySeverityLevel, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::log::v2_mt_posix::sources::single_thread_model>::open_record_unlocked<boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> >(boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> const&) (basic_logger.hpp:259)
==48934== by 0x11825B: boost::log::v2_mt_posix::record boost::log::v2_mt_posix::sources::basic_channel_logger<boost::log::v2_mt_posix::sources::basic_logger<char, boost::log::v2_mt_posix::sources::severity_channel_logger<MySeverityLevel, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::log::v2_mt_posix::sources::single_thread_model>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >::open_record_with_channel_unlocked<boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> >(boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> const&, boost::parameter::void_) (channel_feature.hpp:195)
==48934== by 0x1172B2: boost::log::v2_mt_posix::record boost::log::v2_mt_posix::sources::basic_channel_logger<boost::log::v2_mt_posix::sources::basic_logger<char, boost::log::v2_mt_posix::sources::severity_channel_logger<MySeverityLevel, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::log::v2_mt_posix::sources::single_thread_model>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >::open_record_unlocked<boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> >(boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> const&) (channel_feature.hpp:171)
==48934== by 0x115E8B: boost::log::v2_mt_posix::record boost::log::v2_mt_posix::sources::basic_severity_logger<boost::log::v2_mt_posix::sources::basic_channel_logger<boost::log::v2_mt_posix::sources::basic_logger<char, boost::log::v2_mt_posix::sources::severity_channel_logger<MySeverityLevel, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::log::v2_mt_posix::sources::single_thread_model>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MySeverityLevel>::open_record_unlocked<boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> >(boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> const&) (severity_feature.hpp:253)
==48934== by 0x114961: boost::log::v2_mt_posix::record boost::log::v2_mt_posix::sources::basic_composite_logger<char, boost::log::v2_mt_posix::sources::severity_channel_logger<MySeverityLevel, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::log::v2_mt_posix::sources::single_thread_model, boost::log::v2_mt_posix::sources::features<boost::log::v2_mt_posix::sources::severity<MySeverityLevel>, boost::log::v2_mt_posix::sources::channel<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >::open_record<boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> >(boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> const&) (basic_logger.hpp:575)
==48934== by 0x1135A5: Logger::panic(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (tc0013.cpp:81)
==48934== by 0x11097B: main (tc0013.cpp:120)
==48934==
==48934== 16 bytes in 1 blocks are still reachable in loss record 3 of 6
==48934== at 0x4C3017F: operator new(unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==48934== by 0x512A5BA: boost::detail::add_thread_exit_function(boost::detail::thread_exit_function_base*) (in /usr/lib/x86_64-linux-gnu/libboost_thread.so.1.65.1)
==48934== by 0x4E98C9A: boost::log::v2_mt_posix::sources::aux::get_severity_level() (in /usr/lib/x86_64-linux-gnu/libboost_log.so.1.65.1)
==48934== by 0x11723B: boost::log::v2_mt_posix::sources::aux::severity_level<MySeverityLevel>::set_value(MySeverityLevel) (severity_feature.hpp:135)
==48934== by 0x115E74: boost::log::v2_mt_posix::record boost::log::v2_mt_posix::sources::basic_severity_logger<boost::log::v2_mt_posix::sources::basic_channel_logger<boost::log::v2_mt_posix::sources::basic_logger<char, boost::log::v2_mt_posix::sources::severity_channel_logger<MySeverityLevel, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::log::v2_mt_posix::sources::single_thread_model>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MySeverityLevel>::open_record_unlocked<boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> >(boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> const&) (severity_feature.hpp:252)
==48934== by 0x114961: boost::log::v2_mt_posix::record boost::log::v2_mt_posix::sources::basic_composite_logger<char, boost::log::v2_mt_posix::sources::severity_channel_logger<MySeverityLevel, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::log::v2_mt_posix::sources::single_thread_model, boost::log::v2_mt_posix::sources::features<boost::log::v2_mt_posix::sources::severity<MySeverityLevel>, boost::log::v2_mt_posix::sources::channel<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >::open_record<boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> >(boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> const&) (basic_logger.hpp:575)
==48934== by 0x1135A5: Logger::panic(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (tc0013.cpp:81)
==48934== by 0x11097B: main (tc0013.cpp:120)
==48934==
==48934== 24 bytes in 1 blocks are still reachable in loss record 4 of 6
==48934== at 0x4C3017F: operator new(unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==48934== by 0x4E98C84: boost::log::v2_mt_posix::sources::aux::get_severity_level() (in /usr/lib/x86_64-linux-gnu/libboost_log.so.1.65.1)
==48934== by 0x11723B: boost::log::v2_mt_posix::sources::aux::severity_level<MySeverityLevel>::set_value(MySeverityLevel) (severity_feature.hpp:135)
==48934== by 0x115E74: boost::log::v2_mt_posix::record boost::log::v2_mt_posix::sources::basic_severity_logger<boost::log::v2_mt_posix::sources::basic_channel_logger<boost::log::v2_mt_posix::sources::basic_logger<char, boost::log::v2_mt_posix::sources::severity_channel_logger<MySeverityLevel, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::log::v2_mt_posix::sources::single_thread_model>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MySeverityLevel>::open_record_unlocked<boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> >(boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> const&) (severity_feature.hpp:252)
==48934== by 0x114961: boost::log::v2_mt_posix::record boost::log::v2_mt_posix::sources::basic_composite_logger<char, boost::log::v2_mt_posix::sources::severity_channel_logger<MySeverityLevel, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::log::v2_mt_posix::sources::single_thread_model, boost::log::v2_mt_posix::sources::features<boost::log::v2_mt_posix::sources::severity<MySeverityLevel>, boost::log::v2_mt_posix::sources::channel<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >::open_record<boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> >(boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> const&) (basic_logger.hpp:575)
==48934== by 0x1135A5: Logger::panic(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (tc0013.cpp:81)
==48934== by 0x11097B: main (tc0013.cpp:120)
==48934==
==48934== 24 bytes in 1 blocks are still reachable in loss record 5 of 6
==48934== at 0x4C3017F: operator new(unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==48934== by 0x512A1BC: boost::detail::make_external_thread_data() (in /usr/lib/x86_64-linux-gnu/libboost_thread.so.1.65.1)
==48934== by 0x512A5AD: boost::detail::add_thread_exit_function(boost::detail::thread_exit_function_base*) (in /usr/lib/x86_64-linux-gnu/libboost_thread.so.1.65.1)
==48934== by 0x4E98C9A: boost::log::v2_mt_posix::sources::aux::get_severity_level() (in /usr/lib/x86_64-linux-gnu/libboost_log.so.1.65.1)
==48934== by 0x11723B: boost::log::v2_mt_posix::sources::aux::severity_level<MySeverityLevel>::set_value(MySeverityLevel) (severity_feature.hpp:135)
==48934== by 0x115E74: boost::log::v2_mt_posix::record boost::log::v2_mt_posix::sources::basic_severity_logger<boost::log::v2_mt_posix::sources::basic_channel_logger<boost::log::v2_mt_posix::sources::basic_logger<char, boost::log::v2_mt_posix::sources::severity_channel_logger<MySeverityLevel, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::log::v2_mt_posix::sources::single_thread_model>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MySeverityLevel>::open_record_unlocked<boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> >(boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> const&) (severity_feature.hpp:252)
==48934== by 0x114961: boost::log::v2_mt_posix::record boost::log::v2_mt_posix::sources::basic_composite_logger<char, boost::log::v2_mt_posix::sources::severity_channel_logger<MySeverityLevel, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::log::v2_mt_posix::sources::single_thread_model, boost::log::v2_mt_posix::sources::features<boost::log::v2_mt_posix::sources::severity<MySeverityLevel>, boost::log::v2_mt_posix::sources::channel<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >::open_record<boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> >(boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> const&) (basic_logger.hpp:575)
==48934== by 0x1135A5: Logger::panic(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (tc0013.cpp:81)
==48934== by 0x11097B: main (tc0013.cpp:120)
==48934==
==48934== 440 bytes in 1 blocks are still reachable in loss record 6 of 6
==48934== at 0x4C3017F: operator new(unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==48934== by 0x512A03D: boost::detail::make_external_thread_data() (in /usr/lib/x86_64-linux-gnu/libboost_thread.so.1.65.1)
==48934== by 0x512A5AD: boost::detail::add_thread_exit_function(boost::detail::thread_exit_function_base*) (in /usr/lib/x86_64-linux-gnu/libboost_thread.so.1.65.1)
==48934== by 0x4E98C9A: boost::log::v2_mt_posix::sources::aux::get_severity_level() (in /usr/lib/x86_64-linux-gnu/libboost_log.so.1.65.1)
==48934== by 0x11723B: boost::log::v2_mt_posix::sources::aux::severity_level<MySeverityLevel>::set_value(MySeverityLevel) (severity_feature.hpp:135)
==48934== by 0x115E74: boost::log::v2_mt_posix::record boost::log::v2_mt_posix::sources::basic_severity_logger<boost::log::v2_mt_posix::sources::basic_channel_logger<boost::log::v2_mt_posix::sources::basic_logger<char, boost::log::v2_mt_posix::sources::severity_channel_logger<MySeverityLevel, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::log::v2_mt_posix::sources::single_thread_model>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, MySeverityLevel>::open_record_unlocked<boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> >(boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> const&) (severity_feature.hpp:252)
==48934== by 0x114961: boost::log::v2_mt_posix::record boost::log::v2_mt_posix::sources::basic_composite_logger<char, boost::log::v2_mt_posix::sources::severity_channel_logger<MySeverityLevel, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::log::v2_mt_posix::sources::single_thread_model, boost::log::v2_mt_posix::sources::features<boost::log::v2_mt_posix::sources::severity<MySeverityLevel>, boost::log::v2_mt_posix::sources::channel<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >::open_record<boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> >(boost::parameter::aux::tagged_argument<boost::log::v2_mt_posix::keywords::tag::severity, MySeverityLevel const> const&) (basic_logger.hpp:575)
==48934== by 0x1135A5: Logger::panic(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (tc0013.cpp:81)
==48934== by 0x11097B: main (tc0013.cpp:120)
==48934==
==48934== LEAK SUMMARY:
==48934== definitely lost: 0 bytes in 0 blocks
==48934== indirectly lost: 0 bytes in 0 blocks
==48934== possibly lost: 0 bytes in 0 blocks
==48934== still reachable: 520 bytes in 6 blocks
==48934== suppressed: 0 bytes in 0 blocks
==48934==
==48934== For counts of detected and suppressed errors, rerun with: -v
==48934== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
In my real application the Logger class lives in a library, that's why I need to properly terminate it (the termination is performed by the systemctl). However, I still see exceptions in syslog during the exit from my application:
terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::log::v2_mt_posix::system_error> >'
I think that finding a way to get rid of these "520 bytes in 6 blocks" after exit will help me to terminate my application clearly.
How to write the terminate function (see above) correctly - in order not to leave anything in Boost Log internals reachable?
Inspired by the @user7860670 answer, I'm (after many years!) answering my own question. The test below doesn't leak memory after the exit from it - the idea is to do all the logging in a separate consumer thread, and to send logging messages to this thread via a blocking queue.
#include <iostream>
#include <string>
#include <condition_variable>
#include <mutex>
#include <queue>
#include <thread>
#include <boost/log/common.hpp>
#include <boost/log/sources/logger.hpp>
#include <boost/log/utility/setup/file.hpp>
#include <boost/phoenix/bind/bind_member_function.hpp>
#include <boost/shared_ptr.hpp>
namespace bl = boost::log;
namespace bp = boost::phoenix;
enum class MySeverityLevel
{
panic,
alert,
critical,
error,
warning,
notice,
info,
debug
};
BOOST_LOG_ATTRIBUTE_KEYWORD(Severity, "Severity", MySeverityLevel)
BOOST_LOG_ATTRIBUTE_KEYWORD(Channel, "Channel", std::string)
class Logger
{
public:
Logger(std::string const& CH, MySeverityLevel const SEV):
m_channel(CH), m_severityMax(SEV), m_thr(&Logger::consumer, this)
{
}
~Logger()
{
this->terminate();
}
void terminate()
{
m_thr.request_stop();
}
void panic(std::string const& S)
{
this->push({S, MySeverityLevel::panic});
}
void debug(std::string const& S)
{
this->push({S, MySeverityLevel::debug});
}
private:
using LogMessage = struct {std::string txt; MySeverityLevel level;};
void push(LogMessage const& MSG)
{
std::lock_guard lock(m_mtx);
m_que.push(MSG);
m_cnd.notify_one();
}
bool pop(LogMessage& MSG)
{
std::unique_lock lock(m_mtx);
if (m_cnd.wait(lock, m_thr.get_stop_token(), [this](){return not m_que.empty();}))
{
MSG = m_que.front();
m_que.pop();
return true;
}
else
{
return false;
}
}
using ChannelValue = bl::value_ref<std::string, tag::Channel>;
using MySeverityLevelValue = bl::value_ref<MySeverityLevel, tag::Severity>;
bool filter(ChannelValue const& CH, MySeverityLevelValue const& SEV) const
{
if (CH && SEV)
{
return (CH.get() == m_channel) && (SEV.get() <= m_severityMax);
}
else
{
return false;
}
}
void consumer()
{
// ------ initialization
bl::sources::severity_channel_logger<MySeverityLevel, std::string> log(bl::keywords::channel = m_channel);
auto const snk = bl::add_file_log
(
bl::keywords::file_name = m_channel + ".log",
bl::keywords::filter = bp::bind(&Logger::filter, this, Channel.or_none(), Severity.or_none())
);
// ------ main loop
while (true)
{
LogMessage msg;
if (this->pop(msg))
{
BOOST_LOG_SEV(log, msg.level) << msg.txt;
}
else
{
break;
}
}
// ------ termination
bl::core::get()->remove_sink(snk);
snk->flush();
}
std::string const m_channel;
MySeverityLevel const m_severityMax;
std::queue<LogMessage> m_que;
std::condition_variable_any m_cnd;
std::mutex m_mtx;
std::jthread m_thr;
};
int main()
{
Logger lgA("A", MySeverityLevel::error);
lgA.panic("A: Panic");
lgA.debug("A: Debug");
lgA.terminate();
}
It looks like there is a perfect coexistence between Boost threads (from the boost::log) and standard C++ jthread, which I've chosen because of its ability to be smoothly stopped.