Re: openr and /get_lun

[davidf(at)dfanning.com (David Fanning)]

Craig Markwardt (craigmnet@cow.physics.wisc.edu) writes:

> I have noticed that the use of /GET_LUN and ERROR keywords to openr is
> not as helpful as I would have hoped.  Do other have this experience?
> The problem is that when an error occurs, it is hard to know whether
> the file unit was "gotten" or not.
> 
> For example:
> 
> pro test1
>   openr, unit, filename, /get_lun, error=err
>   free_lun, unit
> end
> 
> If there was an error, then it is possible that UNIT was never set,
> and is hence undefined.  FREE_LUN doesn't take undefined variables.
> 
> If there is error checking to do, I don't know exactly what it should
> be.  So I find myself explicitly doing this instead:
> 
> pro test2
>   get_lun, unit
>   openr, unit, filename, error=err
>   free_lun, unit
> end
> 
> Comments?

I guess I'd use the ol' IF N_Elements(lun) NE 0 THEN Free_Lun, lun

Cheers,

David

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