LTWAINTEMPLATECALLBACK Function

#include "lttwn.h"

L_INT pEXT_CALLBACK YourFunction (hSession, pCapability, nStatus, pUserData)

HTWAINSESSION hSession;	/* handle to an existing TWAIN session */
pTW_CAPABILITY * pCapability;	/* pointer to a capability */
L_INT nStatus;	/* indicates success or error code */
L_VOID * pUserData;	/* pointer to additional parameters */

Called for each capability being loaded from the template file or saved from the TWAIN source. The address of this callback is passed as an argument L_TwainLoadTemplateFile and L_TwainSaveTemplateFile.

Parameter	Description
hSession	Handle to an existing TWAIN session.
pCapability	Pointer to a TW_CAPABILITY structure that contains the capability. For information on this structure, refer to www.twain.org and click on TWAIN Specification.
nStatus	When used with L_TwainLoadTemplateFile, nStatus refers to whether pCapability was set successfully. When used with L_TwainSaveTemplateFile, nStatus refers to whether the pCapability was successfully added to the template file.
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_TwainLoadTemplateFile or L_TwainSaveTemplateFile.)
	Keep in mind that this is a void pointer, which must be cast to the appropriate data type within your callback function.

Returns

TWAIN_SUCCESS	The function was successful.
TWAIN_SUCCESS_ABORT	The callback wants to abort the operation.
< 1	An error occurred. Refer to Return Codes.

Comments

Use this callback to alert the user of any failures in setting a capability when loaded from a template file. You can also use this callback to provide a listing of all capabilities and their possible values found in a template file or being saved to a template file.

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_TwainLoadTemplateFile, L_TwainSaveTemplateFile
Topics:	TWAIN Functionality: Callbacks