Query current State?

[clivew]

I can not find a call that returns the current state of a source.
Is there one?

I am running into some predictable but intermittent failures (I know the steps to reproduce it; but, so far, have not figured out what is different) when changing the CAP_DUPLEXENABLED value and I would like to be able to check the state of the source before making the call as part of my debugging process.

MSG_GET always works; but that does not have to be in state 4 as far as I can read the specifications.

FYI: Current scanner in question is Canon DR-2510C

Any suggestions welcomed.

Clive

[gabe]

there isn’t a call to get the current state, you need to track it.

check a known source, Canon don’t have a great reputation – run a Kodak driver (like an i30/i40) in simulation mode.

EDITED: there wasn’t one in the 1.9 spec

[clivew]

Thanks gabe.
That is what it looked like.

Tracking it is not much use for debugging.
I had a call that was failing and wanted to check the current state in case it had somehow changed on me and I had lost track.

The truth turned out to be that trying to set CAP_DUPLEXENABLED to True for the Canon DR-2510C fails if CAP_XFERCOUNT is currently 1 (one).
Any other value does does not fail for example 3.

If you want to follow the TWAIN Capability Ordering documentation you have to set CAP_XFERCOUNT twice.
Once before CAP_DUPLEXENABLED to any acceptable value (e.g. 2) and once in its proper place near the end to the actual value you want.

Clive

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