Trivial (policy based) C++ logger

I was looking for simple logger to my C++ projects. In last I write my own

fast start with zeroconfig ability

#include "logxx.hpp"

int main() {
  // registrate new logger "channel" with sink file_channel
  logxx::logger::log("file").channel(new logxx::file_channel("app.log"));

  LOG(debug) << "This message goes to std::cerr" << std::endl;

  LOG_("file",debug) << "And this to file app.log" << std::endl;

  LOG_("on-fly",debug) <<  "You can create channels on fly" << std::endl;

  logxx::logger::log().filter(logxx::info); // setup minimal logging level
  LOG(debug) << "This message is now dropped because filter" << std::endl;

  // mute root logger
  logxx::logger::log().channel(new logxx::null_channel);
  LOG(error) << "Now is everything dropped" << std::endl;

  LOG_("on-fly",info) << "\"on-fly\" is still send into cerr" << std::endl;

  // unmute root logger
  logxx::logger::log().channel(new logxx::console_channel);
  LOG(info) << "Now we are in back in console" << std::endl;


}

help macros to allow disable logging evaluation

#define LOG(level) if (logxx::logger::log().severity() >= logxx::level) logxx::logger::log().get(logxx::level)

original code:

LOG(debug) << someReallyLongTimeConsumingDump() << std::endl;

expanded code:

if (logxx::logger::log().severity() >= logxx::debug) 
    logxx::logger::log().get(logxx::debug) << someReallyLongTimeConsumingDump() << std::endl;

so evaluation of someReallyLongTimeConsumingDump() is just unly when debug severity is enabled

TODO:

• syslog channel
• filter policy with throw exception on fatal
• more flexible formating policy (especialy channel name)
• write doc around policies