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https://issues.apache.org/jira/browse/LOGCXX-361?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13940382#comment-13940382
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Florian Seydoux commented on LOGCXX-361:
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Log4cxx use APR (apr_time_now()) for the timestamp (which offer microseconds
resolution).
It's sadly true that this lib, under windows, get the 'current' time from a
call to GetSystemTime (milliseconds resolution), before transforming it to a
FILETIME (100-ns resolution), and rounding it to the required resolution.
Accordingly to [this post
(stackoverflow)|http://stackoverflow.com/questions/4568221/c-get-system-time-to-microsecond-accuracy-on-windows]
and [the windows timestamp
project|http://www.windowstimestamp.com/description], it seems that directly
calling
[GetSystemTimeAsFileTime|http://msdn.microsoft.com/en-us/library/windows/desktop/ms724397%28v=vs.85%29.aspx]
would, at least under windows vista and later, gives sub-milliseconds
resolution. More accurate timing could be obtained using QueryPerformanceTimer.
Anyway, I would suggest to redirect this request to APR (if not already done).
> 15-16 milliseconds granularity on Windows
> ------------------------------------------
>
> Key: LOGCXX-361
> URL: https://issues.apache.org/jira/browse/LOGCXX-361
> Project: Log4cxx
> Issue Type: Improvement
> Components: Layout
> Environment: Windows NT/2003
> Reporter: Sameer Gupta
> Assignee: Curt Arnold
> Original Estimate: 72h
> Remaining Estimate: 72h
>
> I have noticed the message timestamps being logged are atleast 15-16
> milliseconds apart on windows NT/2003 systems even though the messages
> actually requested to be logged were just couple of milliseconds apart. This
> is due to the functions being used in the log4cxx code which are based on the
> SYSTEMTIME structure. The accuracy of these functions is 15-16 milliseconds
> at the most. I have tried to play around with the code and implemented
> performance counters to produce sub 15-16 milliseconds accuracy between two
> message timestamps. This will specially help the users who develop low
> latency applications.
>
> I am wondering if I can contribute my work to the project. Please let me know
> how I can join the project as a developer and what is the procedure to
> contribute. Opologies, if this has already been implemented.
>
> Regards,
> Sameer
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