Get severity of boost.log logger..?

Question

Suppose I have a simple boost.log severity_logger logger set up like this:

   logging::core::get()->set_filter(logging::trivial::severity >= logging::trivial::debug);
   logging::add_common_attributes();
   src::severity_logger< logging::trivial::severity_level > logger;

How would I check the severity programmatically?
I.e. somethinig like logger.getSeverity()..?

I've sifted through the docs and other questions here on StackOverflow but just couldn't find what should be a straightforward API call..?

Answer 1

I would say you cannot. The logging system is layered in three layers (see Design overview of the logging system).

• Your severity_logger is a source logger with attribute severity_level within the data collection layer.

• The severity you set with logging::core::get()->set_filter(...) is a function object, that set for the logging core. All messages passed to a logger will get filtered by that function object, before being passed to the sinks.

So, there is actually no such thing as severity is the severity_logger. The severity is just passed to the core and then to the sinks.

---

EDIT: Elaborating on my comment, you could also declare a variable severityLevel and pass it to the set_filter function (using boost's reference wrapper boost::ref())

// defined somewhere:
logging::trivial::severity_level severityLevel = logging::trivial::info;

// passed to set_filter() by reference
logging::core::get()->set_filter(
    logging::trivial::severity >= boost::ref(severityLevel));

// try out the logging:
BOOST_LOG_SEV(logger, warning) << "A warning severity message"; // not filtered out
severityLevel = logging::trivial::error;
BOOST_LOG_SEV(logger, warning) << "Another warning message"; // filtered out