#include "lttwn.h"

L_VOID pEXT_CALLBACK YourFunction (hSession, nPage, pszFileName, bFinishScan, pUserData)


handle to an existing TWAIN session

L_INT nPage;

page number

L_TCHAR * pszFileName;

File name

L_BOOL bFinishScan;

flag to determine if the scanning status

L_VOID *pUserData;

pointer to additional parameters

Called twice for each scanned page. The address of this callback is passed as an argument to the L_TwainAcquireMulti function.

Parameter Description
hSession Handle to an existing TWAIN session. This handle is obtained by calling the L_TwainInitSession or L_TwainInitSession2 function.
nPage Number of the page being acquired
pszFileName Character string containing the name of the file in which to save the scanned image(s).
bFinishScan Flag that indicates the scanning status. Possible values are:
  Value Meaning
  TRUE Scanning of the page has finished.
  FALSE Scanning of the page has just started.
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_TwainAcquireMulti.)
  Keep in mind that this is a void pointer, which must be cast to the appropriate data type within your callback function


This callback will be called two times. The callback is called the first time when the Twain source begins scanning the page. The callback is called the second time when the Twain source has finished scanning the page.

Required DLLs and Libraries


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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