未写入提升日志文件

我已经在boost日志上挣扎了一段时间了——我得到了他们写日志文件的简单示例(http://boost-log.sourceforge.net/libs/log/example/doc/tutorial_file.cpp)。然而，当我试图将该代码复制到"Logger"类中时，我无法将其写入日志文件。我可以看到文件default.log被创建，但里面什么都没有

我是debian 7 64位。一切编译精细-编译行是：

g++ -o build/Logger.o -c -std=c++11 -Wall -g -O0 -DBOOST_LOG_DYN_LINK -DDEBUG src/Logger.cpp
g++ -o build/logtest build/Logger.o -lboost_log -lboost_log_setup -lboost_date_time -lboost_thread -lboost_wave -lboost_regex -lboost_program_options

这是我的代码：

Logger.cpp

/*
 * Logger.cpp
 *
 *  Created on: 2011-01-17
 *      Author: jarrett
 */
#include "Logger.h"
namespace logging = boost::log;
namespace sinks = boost::log::sinks;
namespace src = boost::log::sources;
namespace expr = boost::log::expressions;
namespace attrs = boost::log::attributes;
namespace keywords = boost::log::keywords;
namespace dhlogging {
Logger::Logger(std::string fileName)
{
    initialize(fileName);
}
Logger::Logger(Logger const&)
{
}
Logger::~Logger()
{
}
Logger* Logger::logger_ = nullptr;
Logger* Logger::getInstance(std::string logFile)
{
    if ( Logger::logger_ == nullptr ) {
        logging::add_file_log( logFile );
        logging::core::get()->set_filter
        (
            logging::trivial::severity >= logging::trivial::info
        );
        logging::add_common_attributes();
        Logger::logger_ = new Logger(logFile);
    }
    return Logger::logger_;
}
void Logger::initialize(std::string fileName)
{   
    BOOST_LOG(log_) << "Hello, World!";
    BOOST_LOG_SEV(log_, info) << "Hello, World2!";
}
void Logger::logInfo(std::string message)
{
    BOOST_LOG_SEV(log_, info) << message;
}
void Logger::logDebug(std::string message)
{
    BOOST_LOG_SEV(log_, debug) << message;
}
void Logger::logWarn(std::string message)
{
    BOOST_LOG_SEV(log_, warning) << message;
}
void Logger::logError(std::string message)
{
    BOOST_LOG_SEV(log_, error) << message;
}
void Logger::logFatal(std::string message)
{
    BOOST_LOG_SEV(log_, fatal) << message;
}
}
int main(int, char*[])
{
    logging::add_common_attributes();
    using namespace logging::trivial;
    dhlogging::Logger::getInstance()->logInfo("himom");
    return 0;
}

Logger.h

/*
 * Logger.h
 *
 *  Created on: 2011-01-17
 *      Author: jarrett
 */
#ifndef LOGGER_H_
#define LOGGER_H_
#include <map>
#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/utility/setup/file.hpp>
#include <boost/log/utility/setup/common_attributes.hpp>
#include <boost/log/sources/severity_logger.hpp>
#include <boost/log/sources/record_ostream.hpp>
namespace logging = boost::log;
namespace sinks = boost::log::sinks;
namespace src = boost::log::sources;
namespace expr = boost::log::expressions;
namespace attrs = boost::log::attributes;
namespace keywords = boost::log::keywords;
using namespace logging::trivial;
namespace dhlogging {
class Logger {
public:
    static Logger* getInstance(std::string logFile = "default.log");
    void logInfo(std::string message);
    void logDebug(std::string message);
    void logWarn(std::string message);
    void logError(std::string message);
    void logFatal(std::string message);

private:
    Logger(std::string fileName);
    Logger(Logger const&);
    Logger& operator=(Logger const&);
    virtual ~Logger();
    void initialize(std::string fileName);
    src::severity_logger< severity_level > log_;
    static Logger* logger_; // singleton instance
};
}
#endif /* LOGGER_H_ */