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<== Date ==> <== Thread ==>

Subject: Re: caget.c patch for dynamic array sizing
From: "Johnson, Andrew N." <[email protected]>
To: Ralph Lange <[email protected]>
Cc: EPICS Tech-Talk <[email protected]>
Date: Thu, 30 Jan 2014 01:27:05 +0000
Hi Ralph,

There is one option common to all the catools, the -w delay time, and I could see users wanting to be able to set that, but I don't think it's necessary to provide a global option as long as we have one for each of the individual tools.

Should the Perl versions read those environment variables too? Not all of the options are identical (or even provided in some cases) for the Perl programs.

- Andrew

-- 
Sent from my iPad

> On Jan 29, 2014, at 3:05 AM, "Ralph Lange" <[email protected]> wrote:
> 
>> On 27.01.2014 21:56, Andrew Johnson wrote:
>> Hi Bruce,
>> 
>>> On 01/24/2014 06:32 PM, Bruce Hill wrote:
>>> We've been trying to reduce network bandwidth on
>>> CA image transfers by using ROI to reduce the required
>>> data, and just noticed that the default for the caget
>>> command line tool always fetches the full array, even
>>> if NORD is less than NELM.
>>> 
>>> This happens because caget currently defaults to synchronous
>>> get, and only the -c async option supports dynamic array sizing.
>>> 
>>> As async vs sync CA is a subtle distinction that doesn't matter for
>>> most of our users, I've added an option to our caget to request
>>> synchronous get and changed the default to async.
>>> 
>>> I think this could be useful for the broader community,
>>> so here's a patch that does this.
>> I could accept using an environment variable to control the default
>> asyn/sync behaviour of the caget/caput tools, but I would be concerned
>> about breaking existing scripts that call them if we were to change
>> their behaviour without at least allowing sites to easily switch back to
>> the old default.
>> 
>> My personal preference would be for the catools programs to take
>> defaults from environment variables like GNU's GREP_OPTIONS variable.
>> Then it would be up to you to add something like
>>     export EPICS_CAGET_OPTIONS=-c
>> to your systems' shell configurations.
>> 
>> Ralph Lange is the maintainer for the catools programs though, so I'm
>> waiting for a response from him.
> 
> That proposal sounds reasonable.
> I will add this to the commandline tools.
> 
> Do you think we will also need a generic EPICS_CATOOLS_OPTIONS variable honored by all catools?
> 
> ~Ralph
> 


Replies:
Re: caget.c patch for dynamic array sizing J. Lewis Muir
References:
caget.c patch for dynamic array sizing Bruce Hill
Re: caget.c patch for dynamic array sizing Andrew Johnson
Re: caget.c patch for dynamic array sizing Ralph Lange

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