LWIASETPROPERTIESCALLBACK

#include "ltwia.h"

L_INT pEXT_CALLBACK YourFunction(hSession, PropertyID, nError, uValueType, pValue, pUserData)

HWIASESSION hSession;

handle to an existing WIA session

L_INT PropertyID;

property defined ID

L_INT nError;

returned error code for property set

L_UINT32 uValueType;

property value type

L_VOID * pValue;

pointer to the value that was set for this property ID

L_VOID * pUserData;

pointer to additional parameters

Called to let the user know that an error occurred during the properties set operation and lets the user aborts or retry. The address of this callback is passed as an argument in L_WiaSetProperties function.

Parameter

Description

hSession

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

PropertyID

The ID of the property that was set using the value specified in the pValue parameter.

nError

The returned error code for certain property set.

uValueType

The value type of the property. For a list of valid value types see Microsoft's documentation of the VARENUM enumeration.

pValue

Void pointer to the value used to set this property.

 

You need to cast this void pointer back to (L_INT) for all the properties in LWIAPROPERTIES structure except for the pguidFormat property, which should be cast to (GUID).

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_WiaSetProperties.)

 

Keep in mind that this is a void pointer, which must be cast to the appropriate data type within your callback function.

Returns

WIA_SUCCESS

The function was successful.

WIA_ABORT

The callback wants to abort the properties set process.

WIA_RETRY

The callback wants to retry the properties set process again.

< 1

An error occurred. Refer to Return Codes.

Comments

This feature is available in version 16 or higher.

Called to let the user know that an error occurred during the properties set operation and lets the user aborts or retry.

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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