我實現了用於記錄的Singleton類。我聲明瞭logging_instance_
的靜態類別名稱support_service::logging_service
上只創建一個實例。 support_service::logging_service
類的 Service_logging呼叫實例,其declear靜態變量::logging_instance_
但顯示錯誤對Singleton類的靜態成員函數的未定義引用
undefined reference to `support_service::logging_service<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, int>::logging_service()' collect2: ld returned 1 exit status
support_service.hpp
namespace support_service
{
template<typename PATH = std::string , typename LEVEL = int>
class logging_service
{
public:
static boost::shared_ptr<logging_service<PATH,LEVEL> > instance();
....
private:
logging_service();
logging_service(const logging_service<PATH,LEVEL>&);
static boost::shared_ptr<logging_service<PATH,LEVEL> > logging_instance_;
};
}
template<typename PATH, typename LEVEL>
boost::shared_ptr<logging_service<PATH,LEVEL> > logging_service<PATH,LEVEL>::instance()
{
if(logging_instance_.get() == NULL)
logging_instance_ = boost::shared_ptr<logging_service<PATH,LEVEL> >(new logging_service<PATH,LEVEL>``());
return logging_instance_;
}
service_logging.hpp
using namespace support_service;
template<typename PATH, typename LEVEL>
boost::shared_ptr<logging_service<PATH,LEVEL> >support_service::logging_service<PATH,LEVEL>::logging_instance_;
namespace service_logging
{
template<typename PATH = std::string, typename LEVEL = int>
class service_logging
{
public:
service_logging();
bool set_logging(PATH file_path);
};
}
template<typename PATH, typename LEVEL>
bool service_logging<PATH,LEVEL>::set_logging(PATH file_path)
{
boost::shared_ptr<logging_service<PATH,LEVEL> > logging_ = logging_service<PATH,LEVEL>::instance();
...
}
你不能正確格式化你的代碼嗎?你不知道它有多嚴重嗎? – Nawaz 2012-03-25 07:32:08
另外,使用單身人士 - >不要同情。 – Puppy 2012-03-25 07:34:08