[Fwd: Re: [Linux-gpib-general] using python extension without root]

[daniele p. <pag...@ya...>]

I think that corresponding to the interface there is a file named 
/dev/gpib or /dev/gpib0.

Try chmod 777 /dev/gpib*
I'm not sure... i'm not working with gpib for the moment and don't have 
access to the machine where I worked.

BTW, python is a very good choose :)
I used it with ctypes importing directly the functions from the C 
library and worked fine.

Bye,
daniele

Tate Wilson ha scritto:

> Daniele,
> Thanks for the reply.  You are correct that the libraries are 
> available to an ordinary user after running  gpib_config as root.  But 
> the python module seems to need further root input.  The functions in 
> the python module, such as gpib.write() or gpib.read() take a device 
> id as an argument.  This id is set using gpib.find(), but this can 
> only be done by root.  So, for example, I have a voltmeter at address 
> 4 and there is an entry for it in /etc/gpib.conf  .  I can access it 
> as a regular user using C or using example scripts that came with 
> linux-gpib, so I know it works.  The following python works if I run 
> it as root, but fails on the gpib.find() call if I run it as an 
> ordinary user:
>
> >>>import gpib
> >>>dmm = gpib.find('voltmeter')
> >>>gpib.write(dmm, 'F1R1X')
>
> If I run this as an ordinary user the error is:
>
> >>>dmm = gpib.find('voltmeter')
> libgpib:  ibBoardOpen failed to open device file
> libgpib:  Permission denied
> libgpib:  error in is_cic()!
> libgpib:  ibfind failed to get descriptor
> Traceback (most recent call last):
>    File "<stdin>", line 1, in ?
> gpib.error: Find Error: can't find device!
> >>>
>
> If I don't use gpib.find() at all, I have no way to tell the other 
> functions which device to talk to.
>
> thanks,
> tate
>
>
> daniele paganelli wrote:
>
>> You should configure your devices and interfaces in /etc/gpib.conf 
>> with all necessary information.
>> Then, the only command you need to run from root is "gpib_config", 
>> without any command. All the interfaces and devices you configured 
>> will be available from python or C (as far I have experienced) from 
>> the userspace.
>> So, if you don't want to or you can't run from root that program, you 
>> can try to link it in the rc2.d directory, so it is called at startup.
>> You will not need to call again gpib_config as long as your hardware 
>> configuration doesn't change, or a serious error occur.
>> Anyway, you need root priviledges to modify /etc/gpib.conf and link 
>> gpib_config for autorun, at least one time.
>>
>> hope it works,
>> daniele paganelli
>>
>> Tate Wilson ha scritto:
>>
>>>  Hello all,
>>> I am trying to use the built-in python extension for linux-gpib in a 
>>> data taking program written entirely in python.  The problem is, so 
>>> far I can only get the extension to work running as root, and I need 
>>> it to run as an ordinary user.  The problem seems to be that I have 
>>> to use gpib.find() to set an id for a device, but this function can 
>>> only run as root.  Is that true?  Am I missing something?
>>>
>>> thanks,
>>> tate
>>>
>>>
>>> -------------------------------------------------------
>>> This SF.Net email is sponsored by Oracle Space Sweepstakes
>>> Want to be the first software developer in space?
>>> Enter now for the Oracle Space Sweepstakes!
>>> http://ads.osdn.com/?ad_id=7393&alloc_id=16281&op=click
>>> _______________________________________________
>>> Linux-gpib-general mailing list
>>> Lin...@li...
>>> https://lists.sourceforge.net/lists/listinfo/linux-gpib-general
>>>
>>
>>
>


-- 
))))))))))))))))))))))))))))))))))))))))
Daily Indigest: http://blog.daniele.homelinux.org
Vieni a visitarmi nel mio nuovo blog!
()()))))()))))))))))())))))()()()()())))
()))()))())))))))))())())))()))))))())))
()))()))()))))))))())))()))())))))))))))
()(())))())))))))()))))()))())))))))))))
()))()))())))))))())))())))()))()()())))
()))()))()))))))))())()))))()))))())))))
())())))()()()())))()))))))()()()())))()




-- 
))))))))))))))))))))))))))))))))))))))))
Daily Indigest: http://blog.daniele.homelinux.org
Vieni a visitarmi nel mio nuovo blog!
()()))))()))))))))))())))))()()()()())))
()))()))())))))))))())())))()))))))())))
()))()))()))))))))())))()))())))))))))))
()(())))())))))))()))))()))())))))))))))
()))()))())))))))())))())))()))()()())))
()))()))()))))))))())()))))()))))())))))
())())))()()()())))()))))))()()()())))()