Experimental Physics and
Industrial Control System

Mark Rivers <[email protected]> · Wed, 10 Apr 2013 11:56:56 +0000

I think you can just call the function "fstat" from your C code to determine if the file is present.

If you want to look at all the entries in /dev then you can use the opendir() and readdir() functions.

If your driver knows the names of the files to search for then you can hard-code that in the driver.  If you need to allow the user to specify what to search for then you should implement the asynOctet interface to pass the name.

Mark

________________________________
From: [email protected] [[email protected]] on behalf of Vishnu Patel [[email protected]]
Sent: Wednesday, April 10, 2013 6:24 AM
To: [email protected]
Cc: [email protected]
Subject: Re: linux file search from Asyn

Hi,
    I am ready using asynInt32 for reading and writing I/O channels of board. I want to add one addition functionality which tells operator that perticular board is present or not.
At my linux layer i am have one file correspoing to each board present in the system.

Example-
There are 2 board X and Y is present in the system.
then 2 files /dev/X   and /dev/Y  generated at  boot time.

so if operator want to monitor presence of board X in the system. then if ASYN device support can search /dev/X then board X is in the system and if  /dev/X doesn't exist, that means board X is not present in the system,

So if possible to search file from asyn EPICS device support layer or execute linux file search command from asyn EPICS layer, device support can give information by using BI record that the desirable board is present in the system or not.

Thanks & Regards
Vishnu

From: <[email protected]>
Sent: Wed, 10 Apr 2013 16:03:11
To: <[email protected]>
Cc: <[email protected]>
Subject: Re: linux file search from Asyn

Hi Vishnu,

It sounds like you need an asynPortDriver driver that has a writeOctet method that basically calls system(“string”) or execl( “path”, “arg”, ... ) and catches the response from stdout in the readOctet method. I don’t think such a beast exists but if you took the asynPortDriver documentation (http://www.aps.anl.gov/epics/modules/soft/asyn/R4-21/asynPortDriver.html) and the example I don’t think it would take long to write. You could then use StreamDevice or an asyn record to work out what to do with the reply.

I am posting this to techtalk in case anyone has done this as an exercise and not published it yet.

Cheers,

Nick Rees

Principal Software Engineer           Phone: +44 (0)1235-778430

Diamond Light Source                  Fax:   +44 (0)1235-446713

From: [email protected] [mailto:[email protected]]
Sent: 10 April 2013 10:24
To: Rees, Nick (DLSLtd,RAL,DIA)
Subject: Re: linux file search from Asyn

Hi Nick,

      Actually i want to develop asyn based device support, so that EPICS PV have status of particular board is present or not in the system.

In my linux layer for each board one file is generated in /dev/XXX     at boot time.

so if i can read the XXX file is present or not in /dev directory,  EPICS PV can display the status of perticular board.

Thanks

With regards

Vishnu

From: <[email protected]>
Sent: Wed, 10 Apr 2013 13:48:48
To: <[email protected]>, <[email protected]>
Subject: Re: linux file search from Asyn
HI Vishnu,

You have to provide more information about what you want to do. Do you want to somehow implement an asyn support layer that implements a search (which I don't really understand) or do you just want to find where the asyn support code is in your file system. If the latter, the asyn device support file are in the asyn/devEpics directory of the asyn support module.

Cheers,

Nick Rees
Principal Software Engineer           Phone: +44 (0)1235-778430
Diamond Light Source                  Fax:   +44 (0)1235-446713

From: [email protected]<UrlBlockedError.aspx> [mailto:[email protected]<UrlBlockedError.aspx>] On Behalf Of Vishnu Patel
Sent: 10 April 2013 08:26
To: techtalk
Subject: linux file search from Asyn

Dear all,
          I want to search specific linux file in ayn Device support layer. how is it possible?
Thanks

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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System