LWIAENUMITEMSCALLBACK

#include "ltwia.h"

L_INT pEXT_CALLBACK YourFunction(hSession, nItemsCount, pItem, pUserData)

HWIASESSION hSession;

handle to an existing WIA session

L_INT nItemsCount;

enumerated items count

L_VOID * pItem;

pointer to IWiaItem or IWiaItem2 interfaces

L_VOID * pUserData;

pointer to additional parameters

Called for each found child item for the parent item specified in the L_WiaEnumChildItems function. Also the address of this callback is passed as an argument in L_WiaEnumChildItems.

Parameter

Description

hSession

Handle to an existing WIA session. This handle is obtained by calling the L_WiaInitSession function.

nItemsCount

Enumerated items count.

pItem

Void pointer to IWiaItem or IWiaItem2 interface (the IWiaItem object if using WIA Version 1.0; the IWiaItem2 object if using WIA Version 2.0).

 

Cast this pointer back to IWiaItem* (when using WIA version 1) or IWiaItem2* (when using WIA version 2).

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_WiaEnumChildItems.)

 

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.

ERROR_USER_ABORT

The callback wants to abort the child items enumeration process.

< 1

An error occurred. Refer to Return Codes.

Comments

This feature is available in version 16 or higher.

Called for each child item found for the root item specified through the L_WiaEnumChildItems function. The main purpose of this callback is to find the item for which you are getting or setting the properties.

It is the user responsibility to free the received item by calling the L_WiaFreeItem function.

Required DLLs and Libraries

LTWIA

For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.

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