[sane-devel] Setting backend capabilities

Ralph Little skelband at gmail.com
Sat Mar 7 07:15:17 GMT 2020

I'm implementing a capability for the HP5400C scanner.
There is an LCD display indicating a 2-digit  "copy count" value.

The current value of this can be read by a USB exchange.

The value of it can be modified up or down by some buttons on the 
scanner, but it can also be set in software.

I'm trying to set appropriate capability flags for this but I don't know 
which of the SANE_CAP_*_SELECT is appropriate.

SANE_CAP_SOFT_SELECT indicates that the control can be set by a call to 
SANE_CAP_HARD_SELECT indicates that physical user intervention (like 
setting a switch) can set the value.

The SANE spec says that these are mutually exclusive but it seems that 
this feature requires them both as an option.

Any guide as to what I should be doing here?


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