I asked this question on boost-users mailing list but unfortunately never got a response. Hopefully I'll have better luck here.
I'm trying to specify a format textually (eg, keywords::format = "blahblah", instead of using a compiled expression).
The idea is that the format can be reconfigured easily either through a command line parameter or through the configuration file without needing to recompile. However, it seems that anything specifying %Severity% when using a custom severity_level enum will simply not be output at all.
Take the example from boost_1_55_0/libs/log/example/keywords/main.cpp
Simply changing line 86 to be:
logging::add_console_log(std::clog, keywords::format = "%Severity% %TimeStamp%: %_%");
will exhibit the problem I believe I am trying to resolve.
My suspicion is that the core doesn't know about the custom Severity attribute because it hasn't been registered and so is unable to parse %Severity% to any formatter. In contrast, the add_file_log below that does correctly output the severity level because it uses a compiled expression and is therefore able to deduce what needs to be done (am I correct in that assumption)?
I seem to be unable to add an attribute to resolve this without rolling my own attribute class. How do I add an attribute or formatter related to the Severity which was declared with BOOST_LOG_ATTRIBUTE_KEYWORD? I think it's worth noting that if I remove the template parameter to severity_logger on line 123 so that it matches thus:
src::severity_logger< > slg;
It then devolves into a standard int instead of an enum and the output is "correctly" seen -- as an int and not as a human-readable string. While this is okay for now, I would of course want it to be human-readable if possible. This is as it is in the example in boost_1_55_0/libs/log/example/settings_file/main.cpp.
