LTWAINCAPABILITYCALLBACK Function

#include "lttw2.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.

Functions:	L_TwainEnumCapabilities.
Topics:	TWAIN Functionality: Callback Functions.