Hi Andrey,
-----Opprinnelig melding----- Fra: Boost [mailto:boost-bounces@lists.boost.org] På vegne av Andrey Semashev Sendt: 24. januar 2013 04:30 Til: boost@lists.boost.org Emne: Re: [boost] [log] v2 Initialisation, default sink behaviour and filtering documentation
On January 23, 2013 6:38:45 PM Mats Taraldsvik <mats.taraldsvik@norkart.no> wrote:
Hi,
I am in the process of moving beyond the default sink now, and had some issues. I tried to add the sinks after my logger object had been default initialized, and this caused some problems (partial streams/corruption, mostly). Currently I'm calling core->remove_all_sinks() to remove the default sink. Are there any "best practices" here? Perhaps it would be a good idea to add these "requirements" to the documentation, if they are not there already and I missed them? :)
The default sink cannot be removed, not even with remove_all_sinks. It is used implicitly when no other sinks are added to the core. When you add your sink to the core you automatically suppress the use of the default sink.
As for your problem, could you describe it in more details? A minimal code sample would be useful.
I believe that the corruption was just about flushing buffers correctly, but I can't reproduce it, unfortunately -- I have no problems currently. I found the reason for having to call remove_all_sinks repeatedly : I was initializing multiple logger objects repeatedly, thus adding the sinks to the core multiple times. Unfortunately, I can't avoid this. Is there a better workaround than creating a custom core attribute telling me whether the core has been initialized?
--
I also noticed that the severity filter examples are :
logging::core::get()->set_filter ( logging::trivial::severity >= logging::trivial::info );
From "Setting up sinks", and
sink->set_filter(expr::attr< int >("Severity") >= 2);
(i.e. comparing the Severity with an int) when moving to the more advanced section in "Sink frontends".
Could you adjust one of the examples in "Sink frontends" to use the severity_level type (that the documentation introduces in the tutorial "Adding more information to log: Attributes") directly? For example:
sink->set_filter(expr::attr< severity_level >("Severity") >= sink->warning);
Or explaining this in "Log record formatting".
I had trouble understanding this at first, but I might be the only one :). Thought I'd mention it anyway.
The type of severity level is not mandated by the library, and each section of the documentation is intended to have minimal dependencies on other parts of the library. That's why trivial severity levels are not used in sinks description. I'll think about how to clear this confusion better.
Ok. I understood that the severity_level is allowed to be a custom object. What I did not understand in this context was how to filter the object representing the severity (for trivial::severity it was the object e.g. trivial::fatal, but the advanced documentation compared against an int (I am aware that enums are implicitly casted to ints, but still)). New question: I can't get this (or BOOST_LOG_SCOPED_THREAD_ATTR) to compile: BOOST_LOG_SCOPED_LOGGER_ATTR(_logger, "FID", boost::log::attributes::constant<int>(id)); _logger is a private member reference to a severity_logger Compile errors (more or less equal for BOOST_LOG_SCOPED_THREAD_ATTR): 1>Object.cpp(945): error C2248: 'boost::log::v2s_mt_nt5::aux::scoped_logger_attribute<LoggerT>::scoped_logger_attribute' : cannot access private member declared in class 'boost::log::v2s_mt_nt5::aux::scoped_logger_attribute<LoggerT>' 1> with 1> [ 1> LoggerT=boost::log::v2s_mt_nt5::sources::severity_logger<boost::log::v2s_mt_nt5::trivial::severity_level> 1> ] 1> boost/log/attributes/scoped_attribute.hpp(58) : see declaration of 'boost::log::v2s_mt_nt5::aux::scoped_logger_attribute<LoggerT>::scoped_logger_attribute' 1> with 1> [ 1> LoggerT=boost::log::v2s_mt_nt5::sources::severity_logger<boost::log::v2s_mt_nt5::trivial::severity_level> 1> ]
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