Available in LEADTOOLS Imaging Pro, Vector, Document, and Medical Imaging toolkits. |
#include "lttwn.h"
L_INT pEXT_CALLBACK YourFunction (hSession, uCap, pCapabiltiy, pUserData)
HTWAINSESSION hSession; |
/* handle to an existing TWAIN session */ |
L_UINT uCap; |
/* capability received */ |
pTW_CAPABILITY * pCapability; |
/* pointer to a structure */ |
L_VOID * pUserData; |
/* pointer to additional parameters */ |
Called for each capability enumerated by the L_TwainEnumCapabilities function. The address of this callback is passed as an argument in L_TwainEnumCapabilities.
Parameter |
Description |
hSession |
Handle to an existing TWAIN session. This handle is obtained by calling the L_TwainInitSession function. |
uCap |
The capability being enumerated. For more information on capability values, refer to the Twain 1.9 Specification, available at www.twain.org. |
pCapability |
Pointer to the TW_CAPABILITY structure that references the capability data being enumerated. For more information about TW_CAPABILITY, refer to the TWAIN 1.9 specification from the site http://www.twain.org/. |
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_TwainEnumCapabilities.) |
|
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
To prevent memory leaks, the user should free the pointer to TW_CAPABILITY structure within the callback 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: |
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Topics: |
Example
For an example, refer to L_TwainStartCapsNeg.