L_TwainSetDeviceEventCallback
#include "lttwn.h"
L_LTTWN_API L_INT L_TwainSetDeviceEventCallback(hSession, pfnCallBack, pUserData)
HTWAINSESSION hSession; |
/* handle to an existing TWAIN session */ |
LTWAINDEVICEEVENTCALLBACK pfnCallBack; |
/* callback function */ |
L_VOID * pUserData; |
/* pointer to more parameters for the callback */ |
Sets the device event callback.
Parameter |
Description |
hSession |
Handle to an existing TWAIN session. This handle is obtained by calling the L_TwainInitSession function. |
pfnCallBack |
Pointer to a callback function. The callback function must adhere to the function syntax specified in LTWAINDEVICEEVENTCALLBACK Function. |
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_TwainSetDeviceEventCallback.) 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. |
< 1 |
An error occurred. Refer to Return Codes. |
Comments
This function should be called after calling L_TwainStartCapsNeg function and before calling L_TwainEndCapsNeg function.
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: |
L_TwainStartCapsNeg, L_TwainGetDeviceEventData, L_TwainSetDeviceEventCapability, L_TwainGetDeviceEventCapability, L_TwainResetDeviceEventCapability, LTWAINDEVICEEVENTCALLBACK |
Topics: |
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Example
For an example, refer to L_TwainGetDeviceEventData.