這次演示如何在一個程式中使用兩個sink. 這兩個sink有不同的filter，生成兩個日誌檔案，採用不同的日誌格式。

完整程式碼如下：

#include <fstream>
#include <boost/shared_ptr.hpp>
#include <boost/make_shared.hpp>
#include <boost/log/core.hpp>
#include <boost/log/trivial.hpp>
#include <boost/log/expressions.hpp>
#include <boost/log/sinks/sync_frontend.hpp>
#include <boost/log/sinks/text_ostream_backend.hpp>
#include <boost/log/sources/severity_logger.hpp>
#include <boost/log/sources/record_ostream.hpp>
#include <boost/log/utility/setup/common_attributes.hpp>
#include <boost/log/support/date_time.hpp>
#include <boost/thread/thread.hpp>
#include <boost/log/attributes/scoped_attribute.hpp>
namespace logging = boost::log;
namespace src = boost::log::sources;
namespace expr = boost::log::expressions;
namespace sinks = boost::log::sinks;
namespace keywords = boost::log::keywords;
using namespace logging::trivial;
void InitLog() {
  typedef sinks::synchronous_sink< sinks::text_ostream_backend > text_sink;
  boost::shared_ptr< text_sink > sink1 = boost::make_shared< text_sink >();
  sink1->locked_backend()->add_stream(
         boost::make_shared< std::ofstream >("sign.log"));
  sink1->set_formatter (
         expr::format("[%1%]<%2%>(%3%): %4%")
         % expr::format_date_time< boost::posix_time::ptime >("TimeStamp", "%Y-%m-%d %H:%M:%S")
         % logging::trivial::severity
         % expr::attr<boost::log::attributes::current_thread_id::value_type >("ThreadID")
         % expr::smessage
         );
  logging::core::get()->add_sink(sink1);
  sink1->set_filter(expr::attr< severity_level >("Severity") >= warning);
  boost::shared_ptr< text_sink > sink2 = boost::make_shared< text_sink >();
  sink2->locked_backend()->add_stream(
         boost::make_shared< std::ofstream >("sign.csv"));
  sink2->set_formatter (
         expr::format("%1%,%2%,%3%")
         % expr::format_date_time< boost::posix_time::ptime >("TimeStamp", "%Y-%m-%d %H:%M:%S")
         % logging::trivial::severity
         % expr::smessage
         );
  logging::core::get()->add_sink(sink2);
  sink2->set_filter(expr::attr< severity_level >("Severity") < warning);
  logging::add_common_attributes();
  BOOST_LOG_SCOPED_THREAD_TAG("ThreadID", boost::this_thread::get_id());
}
int main(int, char*[]) {
  InitLog();
  src::severity_logger<severity_level> lg;
  BOOST_LOG_SEV(lg, trace) << "A trace severity message";
  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, fatal) << "A fatal severity message";
  return 0;
}
 

所有嚴重級別大於等於warning的日誌會出現在sign.log檔案中，所有低於warning的日誌會被記錄在sign.csv檔案中，並以csv格式儲存。

執行這個例子會看到兩個檔案的結果：

$ cat sign.csv
2013-12-25 16:31:27,trace,A trace severity message
2013-12-25 16:31:27,debug,A debug severity message
2013-12-25 16:31:27,info,An informational severity message 
$ cat sign.log
[2013-12-25 16:31:27]<warning>(0x00007f64b5cf3740): A warning severity message
[2013-12-25 16:31:27]<error>(0x00007f64b5cf3740): An error severity message
[2013-12-25 16:31:27]<fatal>(0x00007f64b5cf3740): A fatal severity message