#include "lttwn.h"
L_INT pEXT_CALLBACK YourFunction (hSession, uCap, nStatus, pValue, pUserData)
HTWAINSESSION hSession; |
handle to an existing TWAIN session |
L_UINT uCap; |
capability being set |
L_INT nStatus; |
status variable |
L_VOID * pValue; |
pointer to the original value |
L_VOID * pUserData; |
pointer to additional parameters |
Called for each property set. The address of this callback is passed as an argument to L_TwainSetProperties.
Parameter |
Description |
hSession |
Handle to an existing TWAIN session. This handle is obtained by calling the L_TwainInitSession or L_TwainInitSession2 function. |
uCap |
The capability being set. |
nStatus |
This variable holds the value of the error that occurred while the property was being set. |
pValue |
Pointer to the original value. The user can cast this depending on the type of the property, and modify it. |
pUserData |
A void pointer that you can use to access a variable or structure containing data that your callback function needs. This gives you a way to receive data indirectly from the function that uses this callback function. (This is the same pointer that you pass in the pUserData parameter of L_TwainSetProperties.) |
|
Keep in mind that this is a void pointer, which must be cast to the appropriate data type within your callback function. |
SUCCESS |
The function was successful. |
TWAIN_SUCCESS_RETRY |
Retry with the new value in *pValue parameter. |
TWAIN_SUCCESS_ABORT |
Abort the negotiation. |
The user should not free the pValue parameter within this callback.
Required DLLs and Libraries
LTTWN For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files to be Included with your Application. |