Re: Suggestion for IOC log server

[Andrew Johnson <anj@aps.anl.gov>]

Hi Lana,

On 2011-05-25 Abadie Lana wrote:
> So in fact we avoid usage of circulate buffer. But if it can be safely
> removed I would prefer then.

You can do anything you like; it's your control system and the EPICS Open 
License gives you carte blanche to modify the EPICS Base source code however 
you like if the code that we ship doesn't meet your requirements.  In this 
case I think we'll be willing to make the change you're asking for, but you do 
have other options as well.

> One thing I don't understand is this sentence:
> 
> **** The only downside appears to be
> that the server code has to scan through the log-file looking for the write
> location if the name doesn't change, but I don't see that as a major
>  problem myself.  Does anyone object to this?
> *****
> 
> What do you mean?

This was a question to others in the EPICS community who are using the 
iocLogServer since the change that you are proposing does modify the behavior 
of the program slightly in response to a SIGHUP without a name change.  The 
current response is to compare the old and new directory names and just print 
a message to stderr if they are the same, but with your change it will always 
close and reopen the log file in this case and search through it to find the 
correct insertion point (see the seekLatestLine() routine).

If there is anyone who objects to that (minor) change I would consider adding 
a command-line option that enables the behavior you want.  I don't think 
anyone is likely to complain, but I want to give the community a chance to 
point out anything that I've missed before I do that.

- Andrew
-- 
Optimization is the process of taking something that works and
replacing it with something that almost works, but costs less.
-- Roger Needham