[sane-devel] Add function sanei_usb_get_endpoint

[m. allan noah]

Good enough reasoning for me. Commit ASAP.

Now, when you modify the magicolor backend to use it, that might be a
new feature :)

allan

On Mon, Jan 31, 2011 at 4:02 PM, Reinhold Kainhofer
<reinhold at kainhofer.com> wrote:
> Am Montag, 31. Januar 2011, um 21:42:04 schrieb m. allan noah:
>> I will not complain if you commit, but I don't understand the point.
>> You are not saving any cycles when you look up the value instead of
>> just setting it. It's the same switch(), touching the same variable.
>> Plus, if you DO decide you need to change it, you now have to call a
>> second function. Your code now does more operations, not less.
>
> Yes, the purpose is not so much about deciding whether one has to use a
> different endpoint in normal operation, but about debugging (so that you can
> see in your own backend if the correct endpoint is used, when things don't
> work). And also about being able to restore the previous value if an endpoint
> is used for use one USB operationr..
>
> With that new function, you can store the old endpoint, change it, do your USB
> operation and restore the old endpoint.
> That might be useful if a scanner uses one endpoint for most operations, but
> another endpoint for some very particular operations. I can imagine that the
> code is clearer if one sets and immediately resets the endpoint for the
> operation(s) on the less-used endpoint.
>
> Cheers,
> Reinhold
>
> --
> ------------------------------------------------------------------
> Reinhold Kainhofer, reinhold at kainhofer.com, http://reinhold.kainhofer.com/
>  * Financial & Actuarial Math., Vienna Univ. of Technology, Austria
>  * http://www.fam.tuwien.ac.at/, DVR: 0005886
>  * LilyPond, Music typesetting, http://www.lilypond.org
>



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