TW_ONEVALUE structure with ItemType string

[xdaiana]

I’m maintaining a TWAIN driver and I encountered a situation where I’m not sure which is the expected/standard behaviour:

I’m receiving a value for setting a capability with ItemType TWTY_STR255. I saw the code example
pOneValue = (pTW_ONEVALUE)GlobalLock(hContainer);
if(pOneValue)
{
pOneValue->ItemType = TWTY_STR32;
pString = (pTW_STR32)&pOneValue->Item;
memcpy(pString, pInString, sizeof(TW_STR32));
GlobalUnlock(hContainer);
pOneValue = NULL;
pString = NULL;
}
which is functioning fine in most situations.
But I have an application (also developed here) which instead of a string sends a pointer, so that the driver has to cast
pString = (pTW_STR32)pOneValue->Item;

My dilemma is:
is this situation compliant with the TWAIN standard? Are there other applications which are expecting the same behaviour of the driver?

Thanks,
Daiana

[Catherine Sea]

Such issue happens. We also got similar problem before.

[MarkM]

The first form is correct, the second form is wrong. In TWAIN the TW_ONEVALUE structure the “Item” field always contains the data, not a pointer to the data…

[xdaiana]

I just saw that Twacker also sends a pointer (char*)
🙁
Now I’m really confused

[MarkM]

I’ll look into that…if true, it’s a bug…

[Author]

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