2010/8/20 Oskar Nordquist
2010/8/20 Olivier Tournaire
OK. However, I do not understand why this formatter (and only this one) goes out of scope. How can I move it to a global scope to avoid the current behavior (std::nothrow works likes a charm)?
The macro BOOST_LOG_SCOPED_THREAD_ATTR registers an attribute at the current scope, and unregisters it when the current scope exits. In your code, this line is used in your class constructor:
BOOST_LOG_SCOPED_THREAD_ATTR("Uptime", attrs::timer);
This attribute will work for every BOOST_LOG() or BOOST_LOG_SEV() issued in the scope where this attribute was registered. In your case, you are doing a log message from the a_test_method_to_see_if_the_logger_is_still_working() function. When this function is executed, the attribute is no longer in scope (as the constructor is already run, hence attribute is no longer in scope) and when the formatting step is done at this time, the attribute does not exist and that is why the exception is thrown. To make this attribute work everywhere you should put the line above that registers the attribute in your main() function before any logging is done.
On second thought, this is what you want to do: boost::log::core::get()->add_global_attribute("Uptime", attrs::timer()); Put this in your constructor before any logging is done. That way you do not have to have any code outside your class.