Boost Log 2.0 : empty Severity level in logs

Question

I'm using Boost-Log 2.0, which has some differences from version 1, and I have a hard time outputting the "Severity" attribute.

I'm using the "Boost.Format-style" formatters

"%TimeStamp% [%Uptime%] (%LineID%) <%Severity%>: %Message%" 

TimeStamp, LineID, and Message are common_attributes. Uptime is an attribute I added using attrs::timer(). I thought that Severity was automatically added when using severity_logger, but apparently it isn't and that's my problem. I get empty severities, eg:

2013-Apr-06 19:21:52.408974 [00:00:00.001337] (3) <>: A warning severity message 

Notice the empty <>. I've tried to add severity using register_simple_formatter_factory but then I get the compiler error :

error: no matching function for call to ‘register_simple_formatter_factory(const char [9])’ 

and I don't get why.

Here's my code :

#include <iostream>   #include <boost/log/common.hpp> #include <boost/log/core.hpp> #include <boost/log/trivial.hpp> #include <boost/log/expressions.hpp> #include <boost/log/sinks/text_file_backend.hpp> #include <boost/log/sinks/sync_frontend.hpp> #include <boost/log/sinks/text_ostream_backend.hpp> #include <boost/log/utility/setup/file.hpp> #include <boost/log/utility/setup/common_attributes.hpp> #include <boost/log/utility/setup/formatter_parser.hpp> #include <boost/log/sources/severity_logger.hpp> #include <boost/log/sources/severity_feature.hpp> #include <boost/log/sources/record_ostream.hpp>  #include <boost/log/attributes.hpp>  using namespace std;  namespace logging = boost::log; namespace expr = boost::log::expressions; namespace attrs = boost::log::attributes; namespace src = boost::log::sources; namespace keywords = boost::log::keywords;  enum severity_level {     DEBUG,     INFO,     WARNING,     ERROR,     CRITICAL };  BOOST_LOG_INLINE_GLOBAL_LOGGER_DEFAULT(my_logger, src::severity_logger_mt< severity_level> )  // The formatting logic for the severity level template< typename CharT, typename TraitsT > inline std::basic_ostream< CharT, TraitsT >& operator<< (     std::basic_ostream< CharT, TraitsT >& strm, severity_level lvl) {     static const char* const str[] =     {         "DEBUG",         "INFO",         "WARNING",         "ERROR",         "CRITICAL"     };     if (static_cast< std::size_t >(lvl) < (sizeof(str) / sizeof(*str)))         strm << str[lvl];     else         strm << static_cast< int >(lvl);     return strm; }  void init() {     // logging::register_simple_formatter_factory< severity_level >("Severity");     logging::add_file_log(             keywords::file_name = "blop.log",             keywords::auto_flush = true,             keywords::open_mode = (std::ios::out | std::ios::app),             keywords::format = "%TimeStamp% [%Uptime%] (%LineID%) <%Severity%>: %Message%"             );     logging::add_common_attributes();     logging::core::get()->add_global_attribute("Uptime", attrs::timer()); }  int main(int argc, const char *argv[]) {     init();     src::severity_logger_mt< severity_level > lg = my_logger::get();     BOOST_LOG_SEV(lg, DEBUG) << "A debug severity message";     BOOST_LOG_SEV(lg, INFO) << "An informational severity message";     BOOST_LOG_SEV(lg, WARNING) << "A warning severity message";     BOOST_LOG_SEV(lg, ERROR) << "An error severity message";     BOOST_LOG_SEV(lg, CRITICAL) << "A critical severity message";     return 0; } 

Notice the commented-out line :

// logging::register_simple_formatter_factory< severity_level >("Severity"); 

which produces the mentioned error.

I compile it with:

g++ main.cpp -Wall -DBOOST_ALL_DYN_LINK  -lboost_system -lboost_log_setup -lboost_log -lboost_filesystem -lboost_date_time -lboost_thread -o main 

Answer 1

Ran into the same problem (blank %Severity% in the log file AND the same compiler error when trying to add the register function). I found that the call to register_simple_formatter_factory should be:

boost::log::register_simple_formatter_factory< boost::log::trivial::severity_level, char >("Severity");