References ▼
Called for each property set. The address of this callback is passed as an argument to L_TwainSetProperties.
#include "lttwn.h"
L_INT pEXT_CALLBACK YourFunction (hSession, uCap, nStatus, pValue, pUserData)
Handle to an existing TWAIN session. This handle is obtained by calling the L_TwainInitSession or L_TwainInitSession2 function.
The capability being set.
This variable holds the value of the error that occurred while the property was being set.
Pointer to the original value. The user can cast this depending on the type of the property, and modify it.
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.
| Value | Meaning |
|---|---|
| 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.
For an example, refer to L_TwainGetProperties.