LTWAINSETPROPERTYCALLBACK Function
#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 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. |
Returns
SUCCESS |
The function was successful. |
TWAIN_SUCCESS_RETRY |
Retry with the new value in *pValue parameter. |
TWAIN_SUCCESS_ABORT |
Abort the negotiation. |
Comments
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. |
See Also
Functions: |
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Topics: |
Example
For an example, refer to L_TwainGetProperties.