L_TwainGetSources

Summary

Gets the available information for the TWAIN sources installed on the system.

Syntax

L_LTTWN_API L_INT L_TwainGetSources (hSession, pfnCallBack, uStructSize, uFlags, pUserData)

Parameters

HTWAINSESSION hSession

Handle to an existing TWAIN session. This handle is obtained by calling the L_TwainInitSession or L_TwainInitSession2 function.

LTWAINSOURCEINFOCALLBACK pfnCallBack

Callback function for processing each enumerated TWAIN source. Use the function pointer as the value of this parameter.

L_TwainGetSources calls this callback function as it gets each TWAIN source. The callback function must adhere to the function prototype described in LTWAINSOURCEINFOCALLBACK Function.

L_UINT uStructSize

Size in bytes, of the structure passed to the LTWAINSOURCEINFOCALLBACK callback function, for versioning. Use sizeof(LTWAINSOURCEINFO).

L_UINT uFlags

Flags that indicate what sources to get. Possible values are:

L_VOID * pUserData

Void pointer that you can use to pass one or more additional parameters that the callback function needs.

To use this feature, assign a value to a variable or create a structure that contains as many fields as you need. Then, in this parameter, pass the address of the variable or structure, casting it to L_VOID *. The callback function, which receives the address in its own pUserData parameter, can cast it to a pointer of the appropriate data type to access your variable or structure. If the additional parameters are not needed, you can pass NULL in this parameter.

Returns

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.

See Also

Functions

• L_TwainSelectSource
• L_TwainInitSession
• L_TwainInitSession2

Topics

• Managing the TWAIN Source
• TWAIN Functionality: Property Functions
• Programming with LEADTOOLS TWAIN Functions

Example

L_INT EXT_CALLBACK TwnSourcesCB(HTWAINSESSION     hSession, 
                                pLTWAINSOURCEINFO pSource, 
                                L_VOID         * pUserData) 
{ 
   UNREFERENCED_PARAMETER(hSession); 
   UNREFERENCED_PARAMETER(pUserData); 
 
   L_TCHAR szBuffer[MAX_PATH]; 
 
   memset(szBuffer, 0, sizeof(szBuffer)); 
   wsprintf(szBuffer, TEXT("Source Name = %s\nSource Version = %s\nProduct Family = %s\nManufacturer = %s\n"), 
            pSource->pszTwnSourceName, 
            (pSource->TwainVersion == TWAIN_VERSION1) ? TEXT("1.0") : TEXT("2.0"), 
            pSource->pszTwnProductFamily, 
            pSource->pszTwnManufacturer); 
 
   MessageBox(NULL, szBuffer, TEXT("Source Info."), MB_OK); 
   return TWAIN_SUCCESS; 
} 
 
L_INT TwainGetSourcesExample(HTWAINSESSION hSession) 
{ 
   L_INT nRet; 
 
   nRet = L_TwainGetSources(hSession, 
                            TwnSourcesCB, 
                            sizeof(LTWAINSOURCEINFO), 
                            LTWAIN_SOURCE_ENUMERATE_ALL, 
                            NULL); 
   if (nRet != SUCCESS) 
   { 
      MessageBox (NULL, TEXT("Error During Enumeration Procedure"), TEXT("ERROR"), MB_OK); 
      return nRet; 
   } 
   return SUCCESS; 
}