You are viewing a plain text version of this content. The canonical link for it is here.
Posted to log4cxx-user@logging.apache.org by sishen <ye...@gmail.com> on 2006/09/17 20:58:49 UTC
Does log4cxx support variable-arguments?
Hey. everyone.
I'm a new user of log4cxx. I want to know whether log4cxx support variable
argument?
I have found the maillist archive, but i haven't got any answers.
for example, like the macro:
#define LOG4CXX_DEBUG<http://logging.apache.org/log4cxx/manual/group__LoggingMacros.html#ga1>(logger,
message)
it only takes two argument. And now i have to combine all argument to a
string.
This is not convenient. I think variable-argument is common for logging
system.
Any advice prefer, :)
Re: Does log4cxx support variable-arguments?
Posted by sishen <ye...@gmail.com>.
yeah. I prefer this way. That's what i want.
Thanks all, :)
On 9/18/06, Derek Baum <de...@paremus.com> wrote:
>
> I've defined my own logging macros that use <sstream>, for example:
>
> > #include <sstream>
> >
> > // define logging macros using streams
> > #define LOG_LOG(_logger_, _level_, _message_) { \
> > if (_logger_->isEnabledFor(_level_)) {\
> > ::std::stringstream sstr;\
> > sstr << _message_;\
> > _logger_->forcedLog(_level_, sstr.str(), LOG4CXX_LOCATION); } }
> >
> > #define LOG_DEBUG(_logger_, _message_) LOG_LOG(_logger_,
> > ::log4cxx::Level::DEBUG, _message_)
> > #define LOG_ERROR(_logger_, _message_) LOG_LOG(_logger_,
> > ::log4cxx::Level::ERROR, _message_)
>
> I can then use something like this:
>
> LOG_ERROR("something nasty happened: status=" << status << ", value=" <<
> value);
>
> This has the effect of allowing multiple arguments (although in fact the
> whole expression is a single macro argument).
> Additionally, it allows easy use of objects ostream methods, to allow
> them to describe their own state/value.
>
> Hope this helps,
>
> Derek
>
>
> Curt Arnold wrote:
> >
> > On Sep 17, 2006, at 1:58 PM, sishen wrote:
> >
> >> Hey. everyone.
> >>
> >> I'm a new user of log4cxx. I want to know whether log4cxx support
> >> variable argument?
> >> I have found the maillist archive, but i haven't got any answers.
> >>
> >> for example, like the macro:
> >> #define LOG4CXX_DEBUG(logger, message)
> >>
> >> it only takes two argument. And now i have to combine all argument
> >> to a string.
> >>
> >> This is not convenient. I think variable-argument is common for
> >> logging system.
> >> Any advice prefer, :)
> >
> >
> > No, however the message parameter can be an expression, the expression
> > could be a function that takes varargs or has multiple signatures.
> > The expression is only evaluated if the threshold is satisified, so if
> > you do something like:
> >
> > LOG4CXX_INFO(logger, logfmt("%s %s %d", arg1, arg2, arg3));
> >
> > The logfmt method would only be called if logger's threshold level is
> > INFO or above (where logfmt would be a method you defined that
> > returned std::string or std::wstring). The LOG4CXX_INFO are
> > preprocessor macros which handle all the details in passing the caller
> > information to the actual logger methods. If they were not
> > preprocessor macros the __LINE__ and __FILE__ would refer the the
> > location of the method implementation, not the caller. As
> > preprocessor macros, they do not have the ability to overload the
> > macro name with multiple definitions for different argument lists.
>
> ________________________________________________________________________
> The information transmitted is intended only for the person(s) or entity
> to which it is addressed and may contain confidential and/or privileged
> material. Any review, retransmission, dissemination or other use of, or
> taking of any action in reliance upon, this information by persons or
> entities other than the intended recipient is prohibited. If you
> received this in error, please contact the sender and delete the
> material from any computer.
>
> Paremus Limited.
> 107-111 Fleet Street, London EC4A 2AB. Phone number +44 20 7936 9098
> ________________________________________________________________________
>
Re: Does log4cxx support variable-arguments?
Posted by Derek Baum <de...@paremus.com>.
I've defined my own logging macros that use <sstream>, for example:
> #include <sstream>
>
> // define logging macros using streams
> #define LOG_LOG(_logger_, _level_, _message_) { \
> if (_logger_->isEnabledFor(_level_)) {\
> ::std::stringstream sstr;\
> sstr << _message_;\
> _logger_->forcedLog(_level_, sstr.str(), LOG4CXX_LOCATION); } }
>
> #define LOG_DEBUG(_logger_, _message_) LOG_LOG(_logger_,
> ::log4cxx::Level::DEBUG, _message_)
> #define LOG_ERROR(_logger_, _message_) LOG_LOG(_logger_,
> ::log4cxx::Level::ERROR, _message_)
I can then use something like this:
LOG_ERROR("something nasty happened: status=" << status << ", value=" <<
value);
This has the effect of allowing multiple arguments (although in fact the
whole expression is a single macro argument).
Additionally, it allows easy use of objects ostream methods, to allow
them to describe their own state/value.
Hope this helps,
Derek
Curt Arnold wrote:
>
> On Sep 17, 2006, at 1:58 PM, sishen wrote:
>
>> Hey. everyone.
>>
>> I'm a new user of log4cxx. I want to know whether log4cxx support
>> variable argument?
>> I have found the maillist archive, but i haven't got any answers.
>>
>> for example, like the macro:
>> #define LOG4CXX_DEBUG(logger, message)
>>
>> it only takes two argument. And now i have to combine all argument
>> to a string.
>>
>> This is not convenient. I think variable-argument is common for
>> logging system.
>> Any advice prefer, :)
>
>
> No, however the message parameter can be an expression, the expression
> could be a function that takes varargs or has multiple signatures.
> The expression is only evaluated if the threshold is satisified, so if
> you do something like:
>
> LOG4CXX_INFO(logger, logfmt("%s %s %d", arg1, arg2, arg3));
>
> The logfmt method would only be called if logger's threshold level is
> INFO or above (where logfmt would be a method you defined that
> returned std::string or std::wstring). The LOG4CXX_INFO are
> preprocessor macros which handle all the details in passing the caller
> information to the actual logger methods. If they were not
> preprocessor macros the __LINE__ and __FILE__ would refer the the
> location of the method implementation, not the caller. As
> preprocessor macros, they do not have the ability to overload the
> macro name with multiple definitions for different argument lists.
________________________________________________________________________
The information transmitted is intended only for the person(s) or entity
to which it is addressed and may contain confidential and/or privileged
material. Any review, retransmission, dissemination or other use of, or
taking of any action in reliance upon, this information by persons or
entities other than the intended recipient is prohibited. If you
received this in error, please contact the sender and delete the
material from any computer.
Paremus Limited.
107-111 Fleet Street, London EC4A 2AB. Phone number +44 20 7936 9098
________________________________________________________________________
Re: Does log4cxx support variable-arguments?
Posted by Curt Arnold <ca...@apache.org>.
On Sep 17, 2006, at 1:58 PM, sishen wrote:
> Hey. everyone.
>
> I'm a new user of log4cxx. I want to know whether log4cxx support
> variable argument?
> I have found the maillist archive, but i haven't got any answers.
>
> for example, like the macro:
> #define LOG4CXX_DEBUG(logger, message)
>
> it only takes two argument. And now i have to combine all argument
> to a string.
>
> This is not convenient. I think variable-argument is common for
> logging system.
> Any advice prefer, :)
No, however the message parameter can be an expression, the
expression could be a function that takes varargs or has multiple
signatures. The expression is only evaluated if the threshold is
satisified, so if you do something like:
LOG4CXX_INFO(logger, logfmt("%s %s %d", arg1, arg2, arg3));
The logfmt method would only be called if logger's threshold level is
INFO or above (where logfmt would be a method you defined that
returned std::string or std::wstring). The LOG4CXX_INFO are
preprocessor macros which handle all the details in passing the
caller information to the actual logger methods. If they were not
preprocessor macros the __LINE__ and __FILE__ would refer the the
location of the method implementation, not the caller. As
preprocessor macros, they do not have the ability to overload the
macro name with multiple definitions for different argument lists.
Re: [SPAM] Does log4cxx support variable-arguments?
Posted by re...@rubixinfotech.com.
Sadly, I don't think so... what we ended up doing was to modify log4cxx to
support the following additional fn()'s:
void debugf(const char *fmt, ...);
void infof(const char *fmt, ...);
void warnf(const char *fmt, ...);
void errorf(const char *fmt, ...);
void fatalf(const char *fmt, ...);
They are each implemented as:
void Logger::debugf(const char* format, ...)
{
if(repository->isDisabled(Level::DEBUG_INT))
{
return;
}
// Format the string
va_list pvar;
va_start(pvar, format);
if(Level::DEBUG->isGreaterOrEqual(getEffectiveLevel()))
{
char MessageBuffer[LOG_MESSAGE_BUFF_SIZE];
vsnprintf(MessageBuffer, sizeof(MessageBuffer), format, pvar);
forcedLog(FQCN, Level::DEBUG, MessageBuffer);
}
}
Renny Koshy
President & CEO
--------------------------------------------
RUBIX Information Technologies, Inc.
www.rubixinfotech.com
sishen
<yedingding@gmail
.com> To
log4cxx-user@logging.apache.org
09/17/2006 02:58 cc
PM
Subject
[SPAM] Does log4cxx support
Please respond to variable-arguments?
"Log4CXX User"
<log4cxx-user@log
ging.apache.org>
Hey. everyone.
I'm a new user of log4cxx. I want to know whether log4cxx support variable
argument?
I have found the maillist archive, but i haven't got any answers.
for example, like the macro:
#define LOG4CXX_DEBUG(logger, message)
it only takes two argument. And now i have to combine all argument to a
string.
This is not convenient. I think variable-argument is common for logging
system.
Any advice prefer, :)