LTWAINCAPABILITYCALLBACK

#include "lttwn.h"

L_INT pEXT_CALLBACK YourFunction (hSession, uCap, pCapabiltiy, pUserData)

Called for each capability enumerated by the L_TwainEnumCapabilities function. The address of this callback is passed as an argument in L_TwainEnumCapabilities.

Parameters

HTWAINSESSION hSession

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

L_UINT uCap

The capability being enumerated. For more information on capability values, refer to the TWAIN specification.

pTW_CAPABILITY * pCapability

Pointer to the TW_CAPABILITY structure that references the capability data being enumerated. For more information about TW_CAPABILITY, refer to the TWAIN specification.

L_VOID * 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_TwainEnumCapabilities.)

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

Returns

Value Meaning
SUCCESS The function was successful.
< 1 An error occurred. Refer to Return Codes.

Comments

To prevent memory leaks, the user should free the pointer to TW_CAPABILITY structure within the callback function.

Required DLLs and Libraries

See Also

Functions

Topics

Example

For an example, refer to L_TwainStartCapsNeg.

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