Home › Forums › TWAIN Classic › DISABLEDS returns TWCC_CAPUNSUPPORTED?
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I believe I’m seeing a Twain Driver bug in the Epson GT-S50 scanner in my Twain application, so I removed my code from the problem and can demonstrate the issue using Twacker alone. Here’s the steps to replicate the issue:
1.) Run Twack_32.exe
2.) File->Select Source…
3.) Select the Epson GT-S50, press the Select button
4.) File->Setup…
5.) Close the Scanner’s UI.
The call to the triplet DG_CONTROL/DAT_USERINTERFACE/MSG_DISABLEDS returns TWRC_FAILURE where the condition code TWCC_CAPUNSUPPORTED.
The call is made in the Twacker source code, DCA_GLUE.c, line 807, in TWDisableDS(). Using the Kodak i40 scanner for example I don’t see this problem following the same steps.
It seems very wrong that calling MSG_DISABLEDS would return unsupported capability, any thoughts?
The TWAIN spec is very clear on the allowed return codes during a failure of the MSG_DISABLEDS operation, and TWCC_CAPUNSUPPORTED is not one of them.
The allowed return codes are:
TWCC_BADDEST
TWCC_SEQERRORYou should only get TWCC_CAPUNSUPPORTED if you are trying to get or set a capability and there is a problem.
@peterp wrote:
The TWAIN spec is very clear on the allowed return codes during a failure of the MSG_DISABLEDS operation, and TWCC_CAPUNSUPPORTED is not one of them.
The allowed return codes are:
TWCC_BADDEST
TWCC_SEQERRORYou should only get TWCC_CAPUNSUPPORTED if you are trying to get or set a capability and there is a problem.
peterp, I filed an incident report with Epson, not sure if it will make it to their Twain driver engineers, but hopefully it can be addressed.
Thanks
In case anyone is interested, this is a driver bug and will be released in a future update by Epson.
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