Re: [Boost-users] Log: [Bug] Setting attribute makes log entry disappear

Subject: Re: [Boost-users] Log: [Bug] Setting attribute makes log entry disappear
From: Florian Lindner (mailinglists_at_[hidden])
Date: 2015-10-12 10:54:21

Florian Lindner wrote:

> Hello,
> 
> I have a tracer, that should log going in and out of a function:
> 
> class Tracer
> {
> public:
>   Tracer(Logger logger, std::string function, std::string file)
>     :
>     _logger(logger),
>     _function(function),
>     _file(file)
>   {}
>   
>   ~Tracer()
>   {
>     using namespace boost::log;
>     //
>     attribute_cast<attributes::mutable_constant<int>>(core::get()-
>get_global_attributes()["Line"]).set(1);
>     attribute_cast<attributes::mutable_constant<std::string>>(core::get()-
>get_global_attributes()["File"]).set(_file);
>     attribute_cast<attributes::mutable_constant<std::string>>(core::get()-
>get_global_attributes()["Function"]).set(_function);
>     BOOST_LOG_SEV(_logger, trivial::severity_level::trace) << "Leaving "
>     << _function;
>   }
> 
> private:
>   Logger _logger;
>   std::string _function;
>   std::string _file;
> };
> 
> This works fine, but as soon as I uncomment the line that sets the Line
> attribut I don't get any Leaving messages anymore.
> 
> The attributes are added beforehand like that:
> 
>     using namespace boost::log;
>     add_common_attributes();
>     core::get()->add_global_attribute("Scope", attributes::named_scope());
>     core::get()->add_global_attribute("Rank",
>     attributes::constant<int>(5));
>     core::get()->add_global_attribute("Line",
>     attributes::mutable_constant<int>(5));
>     core::get()->add_global_attribute("File",
>     attributes::mutable_constant<std::string>(""));
>     core::get()->add_global_attribute("Function",
>     attributes::mutable_constant<std::string>(""));
> 
> Setting all other attributes, similiar to Line works fine. I'm puzzled
> because Line does not seem to be a reserved name, it works somewhere else
> and the boost::log sources reveal no relevant usages of that name.

Sorry, forgot to add what the actual problem is: The log message 
(Leaving...) is simply discarded. All log message before and after that are 
printed fine, but this one.