DS problem when CAP_SUPPORTEDCAPS

[gregary]

It can’t work under TWAIN2 Sample App. Can anyone tell me why? Thanks.

//g_DSM_Entry is import from DAT_ENTRYPOINT





case CAP_SUPPORTEDCAPS:

{

TW_ARRAY *array;

TW_UINT16 ItemCount=2;

pCap->ConType=TWON_ARRAY;

if(g_DSM_Entry.DSM_MemAllocate!=0)

{

pCap->hContainer=g_DSM_Entry.DSM_MemAllocate(sizeof(*array)+sizeof(TW_UINT16)*(ItemCount)-sizeof(TW_UINT8));

}

else

{

pCap->hContainer=GlobalAlloc(GHND,sizeof(*array)+sizeof(TW_UINT16)*(ItemCount)-sizeof(TW_UINT8));

}

if(pCap->hContainer)

{

if(g_DSM_Entry.DSM_MemLock!=0)

{

array=(TW_ARRAY*)g_DSM_Entry.DSM_MemLock(pCap->hContainer);

}

else

{

array=(TW_ARRAY*)GlobalLock(pCap->hContainer);

}

array->ItemType=TWTY_UINT16;

array->NumItems=ItemCount;

array->ItemList[0]=CAP_SUPPORTEDCAPS;

array->ItemList[1]=CAP_XFERCOUNT;

if(g_DSM_Entry.DSM_MemUnlock!=0)

{

g_DSM_Entry.DSM_MemUnlock(pCap->hContainer);

}

else

{

GlobalUnlock(pCap->hContainer);

}

}

else

{

m_IndependantCapMap.m_DSConditionCode=TWCC_LOWMEMORY;

twrc=TWRC_FAILURE;

}

break;

}

[MSM]

Hi Gregary,

see declaration of TW_ARRAY:

typedef struct {
TW_UINT16 ItemType;
TW_UINT32 NumItems; /* How many items in ItemList */
TW_UINT8 ItemList[1]; /* Array of ItemType values starts here */
} TW_ARRAY, FAR * pTW_ARRAY;

ItemList is a TW_UINT8, but not TWTY_UINT16.
You have to fill array properly.

TWTY_UINT16 *p_un16Array = (TWTY_UINT16 *)array->ItemList;
p_un16Array[0]=CAP_SUPPORTEDCAPS;
p_un16Array[1]=CAP_XFERCOUNT;

[gregary]

Thanks for your response.
I change my code like this:
((TW_UINT16*)array->ItemList)[0]=CAP_SUPPORTEDCAPS;
((TW_UINT16*)array->ItemList)[0]=CAP_XFERCOUNT;

And i find out the carsh of TWAIN2 sample app is because it call “DG_CONTROL//DAT_CAPABILITY//MSG_GETLABEL//CAP_XFERCOUNT” after “DG_CONTROL//DAT_CAPABILITY//MSG_GET//CAP_SUPPORTEDCAPS” but i didn’t supply this command.

[MSM]

I had such problem before.
And I found two bugs – one in Sample App and one in the Driver

In the Sample App it crashes because the Driver returns TWRC_SUCCESS, but the string was empty.

In the Driver – it must return TWRC_FAILURE/TWCC_CAPBADOPERATION , but not TWRC_SUCCESS if it is not supporting this operation.

[Author]

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