Boost.Log: 为什么显示重复的消息?
Boost.Log: Why it is showing duplicate the message?
我正在学习 Boost.Log 库。我想将消息发送到文件和 std::clog
。我有以下 class:
class logger
{
public:
explicit logger(
const std::string& tag,
const std::string& file,
bool console
)
{
boost::log::register_simple_formatter_factory< boost::log::trivial::severity_level, char >("Severity");
std::string the_format = "[%TimeStamp%] (%LineID%) [%Severity%]";
if(!tag.empty()) {
m_log_.add_attribute(
"Tag",
boost::log::attributes::constant< std::string >( tag )
);
the_format += " [%Tag%]";
}
the_format += ": %Message%";
if(console) {
boost::log::add_console_log(
std::clog,
boost::log::keywords::auto_flush = true,
boost::log::keywords::format = the_format
);
}
if(!file.empty()) {
boost::log::add_file_log(
boost::log::keywords::file_name = file,
boost::log::keywords::auto_flush = true,
boost::log::keywords::open_mode = (std::ios::out | std::ios::app),
boost::log::keywords::format = the_format
);
}
}
~logger(void)
{ }
void log(
const std::string& msg
)
{
BOOST_LOG_SEV ( m_log_, boost::log::trivial::info ) << msg;
}
private:
boost::log::sources::severity_logger< boost::log::trivial::severity_level > m_log_;
}; // logger
我有以下 main()
功能:
void x()
{
logger lg("omega", "", true);
lg.log( "Goodbye" );
}
int main(int argc, char** argv)
{
logger lg( "alfa", "", true );
lg.log( "Hello world!!!");
x();
return 0;
}
我不明白为什么显示重复的消息:"Hello world!!!":
[2016-Aug-23 17:51:36.852912] (1) [info] [alfa]: Hello world!!!
[2016-Aug-23 17:51:36.853359] (2) [info] [omega]: Goodbye
[2016-Aug-23 17:51:36.853359] (2) [info] [omega]: Goodbye
更新:抱歉,示例不完整。
logger
的构造函数正在调用 add_console_log()
和 add_file_log()
。如果你构造两次logger
,这些函数也会被调用两次。由于他们添加了全局接收器,因此每个日志条目都将在控制台和您的文件中复制两次。
int main(int argc, char** argv)
{
logger lg1("1", "", true);
logger lg2("2", "", true);
logger lg3("3", "", true);
logger lg4("4", "", true);
lg1.log("test");
}
这将输出:
[2016-Aug-23 13:25:56.468382] (1) [info] [1]: test
[2016-Aug-23 13:25:56.468382] (1) [info] [1]: test
[2016-Aug-23 13:25:56.468382] (1) [info] [1]: test
[2016-Aug-23 13:25:56.468382] (1) [info] [1]: test
您可能需要某种引用计数或标志来仅调用这些函数一次。
我正在学习 Boost.Log 库。我想将消息发送到文件和 std::clog
。我有以下 class:
class logger
{
public:
explicit logger(
const std::string& tag,
const std::string& file,
bool console
)
{
boost::log::register_simple_formatter_factory< boost::log::trivial::severity_level, char >("Severity");
std::string the_format = "[%TimeStamp%] (%LineID%) [%Severity%]";
if(!tag.empty()) {
m_log_.add_attribute(
"Tag",
boost::log::attributes::constant< std::string >( tag )
);
the_format += " [%Tag%]";
}
the_format += ": %Message%";
if(console) {
boost::log::add_console_log(
std::clog,
boost::log::keywords::auto_flush = true,
boost::log::keywords::format = the_format
);
}
if(!file.empty()) {
boost::log::add_file_log(
boost::log::keywords::file_name = file,
boost::log::keywords::auto_flush = true,
boost::log::keywords::open_mode = (std::ios::out | std::ios::app),
boost::log::keywords::format = the_format
);
}
}
~logger(void)
{ }
void log(
const std::string& msg
)
{
BOOST_LOG_SEV ( m_log_, boost::log::trivial::info ) << msg;
}
private:
boost::log::sources::severity_logger< boost::log::trivial::severity_level > m_log_;
}; // logger
我有以下 main()
功能:
void x()
{
logger lg("omega", "", true);
lg.log( "Goodbye" );
}
int main(int argc, char** argv)
{
logger lg( "alfa", "", true );
lg.log( "Hello world!!!");
x();
return 0;
}
我不明白为什么显示重复的消息:"Hello world!!!":
[2016-Aug-23 17:51:36.852912] (1) [info] [alfa]: Hello world!!!
[2016-Aug-23 17:51:36.853359] (2) [info] [omega]: Goodbye
[2016-Aug-23 17:51:36.853359] (2) [info] [omega]: Goodbye
更新:抱歉,示例不完整。
logger
的构造函数正在调用 add_console_log()
和 add_file_log()
。如果你构造两次logger
,这些函数也会被调用两次。由于他们添加了全局接收器,因此每个日志条目都将在控制台和您的文件中复制两次。
int main(int argc, char** argv)
{
logger lg1("1", "", true);
logger lg2("2", "", true);
logger lg3("3", "", true);
logger lg4("4", "", true);
lg1.log("test");
}
这将输出:
[2016-Aug-23 13:25:56.468382] (1) [info] [1]: test
[2016-Aug-23 13:25:56.468382] (1) [info] [1]: test
[2016-Aug-23 13:25:56.468382] (1) [info] [1]: test
[2016-Aug-23 13:25:56.468382] (1) [info] [1]: test
您可能需要某种引用计数或标志来仅调用这些函数一次。