Re: [Log4cplus-devel] RollingFileAppender in Multi threading based application

[Václav Z. <vha...@gm...>]

On 20 November 2013 12:34, qwerty mobile wrote:
> Team,
>
> I am new to this mailing list. I don't have any prior knowledge on log4j as
> well. I want to use this log4cplus in our multi threading based larger
> application.
>
> I have some questions for implementing RollingFileAppender in multi
> threading application.
>
> Ours is a small backup application written in C++ having both client and
> server side components. Multiple clients can connect to the server
> simultaneously and send their backup data. I want to add logs for debugging
> in server side.
>
> This is my idea. I will have separate log file for each backup processing in
> the server side assuming backup name is unique here. Three threads will be
> involved in the server side for processing every backup received from the
> client side.
>
> Can I share the Logger object between the threads processing single backup
> in the server side ?.

Yes, you can do that. Assuming log4cplus has been configured as thread
aware (--enable-threads configure switch; Windows builds are always
thread by default), appenders are thread safe.

> I had planned to achieve this by using a static map
> having backup name as key and Logger object as value here. And then from
> each thread, I will get this logger object from the map and then call the
> logging macros as below,
>
> LOG4CPLUS_XX(LoggerObj, LogMessage); # This happens with the same logger
> object from multiple threads.

This should be fine.

>
> Do I have to use any mutex if I share the same logger object between
> different threads processing same backup ?.

No, the appenders manage mutual exclusion between threads internally.

>
> I have read from some forums that RollingFileAppender does synchronous write
> operations. Please confirm the same.

Yes, this is true.

>
> If you could also point me some examples for my case, it will be very
> helpful.
>
> Thanks in advance,
> Prabu

-- 
VZ