L_TwainAcquire or L_TwainGetProperties hanging - function calls never return

I am having an issue with a Xerox 3655x scanner, there the L_TwainGetProperties() function does not return.
If I comment out this call, then intermittently the L_TwainAcquire() call hangs.

Just wondering if anyone else has experienced this and strategy to resolve.

Edited by user Thursday, May 11, 2017 7:30:14 AM(UTC)  | Reason: Not specified

Hello,

Thank you for posting your question on the LEADTOOLS Technical Support Forums.

The first step would be to ensure that you have the latest drivers for your Xerox scanner. You can do this by going to the manufacturers website and downloading the latest drivers for your specific model.

Then you need to see if you can reproduce this issue using the Twain Main demo located in the LEADTOOLS SDK:


If it works in the demo and not your application, then I would suggest taking a look at the demo code and see what the differences are.

If it doesn't work in the demo, then you will need to try using a tool from Twain.org called Twacker. Twacker is written using pure TWAIN code.

Twacker can be downloaded from here:

http://www.twain.org/doc...11c51000503/Twack-32.msi (32 bit)
http://www.twain.org/doc...11c51000504/Twack-64.msi (64 bit)

In general, if a scanner works with Twacker, it should work with LEADTOOLS. If the scanner has the same problem in Twacker, then the problem lies in the Twain driver and you should contact the manufacturer.

I downloaded Twacker and am experimenting with it now.
In the Twain example program, if I add a call to L_TwainGetProperties(g_hTwain, &TwainProp, sizeof(LTWAINPROPERTIES), LTWAIN_PROPERTIES_GETCURRENT); the program hangs.
If in my own program I skip this then I intermittently get L_TwainAcquire () hangs.

These are high level leadtools functions.

Please advice what to look for with Twack to indicate or test for this.

I ran Twack32 and noticed when using CAP_SUPPORTEDCAPS, the list has a value that displays as it's value rather than a string. this is ICAP_AUTOSIZE 0x1156
Odd that that program doesn't have the string value for that capability.

Ran L_TwainEnumCapabilities() everything seemed normal. Still cant get L_TwainGetProperties() to work.

So the Capability that you are wanting to get the current value of is ICAP_AUTOSIZE? When you try to call L_TwainGetProperties() on that capability, it does not return, but you can call L_TwainEnumCapabilities() on it and it returns the enumeration of the capabilities?

In Twacker, you can do the following to get the current capability:

Run Twack_32
Go to File > Select Source and select your Xerox scanner
Go to Special > 1 Load/Open SM
Then Special > 2 Open Source
Then Special > Send

In this dialog, you can specify the following:

Dest : Source
DG: DG_CONTROL
DAT: DAT_CAPABILITY
MSG: MSG_GET
Capability: ICAP_AUTOSIZE
Container: TWON_ONEVALUE

Then click Send and see what happens.

Please update me with the results of this test.