[Log4cpp-devel] RE: Log4cpp on OpenVMS

[Tony C. <dra...@as...>]

Hi Steve and others,

First, the changes (if made) will be applied to OpenVMS compilations
only. I am not sure if other platforms require the changes.

For the disk caching, in order allow other users to "tail -f" on the
application log real-time. The OS needs to flush the changes to the disk
after each line of the logging. The caching should only be applicable to
within a single line of logging, otherwise there would be a delay for
the last few lines of logging to show up. BTW, the fsync() returns
before the I/O completes. 

I agree it's a tradeoff between real-time feedback or better disk
performance.

Ideas?

Tony

> I am not exactly sure how the OpenVMS file system works, but most file
> systems cache writes in memory before flushing them to disk. This greatly
> increases write performance. I would not (at least in the default case), put
> a fflush or fsync in the code.
> 
> Perhaps an additional method which would allow the application to flush
> write to the disk.
> 
> Steve Ostlind
> PentaSafe Security Technologies
> 713.860.9664
> 
> > -----Original Message-----
> > From:	Tony Cheung [SMTP:dra...@as...]
> > Sent:	Friday, February 01, 2002 4:08 AM
> > To:	log...@li...
> > Subject:	[Log4cpp-devel] Log4cpp on OpenVMS
> > 
> > Hi All,
> > 
> > I'm not sure how many are using the OpenVMS platform here, but I am
> > responsible for the OpenVMS support in log4cpp. (I'm rather new to
> > OpenVMS myself, but I am now building a C/C++ project on it)
> > 
> > I've just found out that in current log4cpp, while the application is
> > logging to a file, other users are not able to see the log file.
> > 
> > After some investigations, I've found we could open the log file in
> > shared mode and in the record mode file format (both OpenVMS specific),
> > so that other users could "tail" on the log file.
> > 
> > fsync() should also be called after evey write, so that other users
> > could see the real-time changes.
> > 
> > Please let me know if it's a good idea to make the changes into CVS, so
> > that I would go ahead and do so.
> > 
> > Tony
> > 
> > P.S. I have subscribed to this mailing list, but somehow I am not
> > receiving anything from it. Hope I am the only one having this problem.
> > 
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