References ▼
Gets the supported capabilities and specified value(s) of each capability.
#include "lttwn.h"
L_LTTWN_API L_INT L_TwainEnumCapabilities (hSession, pfnCallBack, uFlags, pUserData)
Handle to an existing TWAIN session. This handle is obtained by calling the L_TwainInitSession or L_TwainInitSession2 function.
Callback function for processing each enumerated capability. Use the function pointer as the value of this parameter.
L_TwainEnumCapabilities calls this callback function as it gets each TWAIN capability. The callback function must adhere to the function prototype described in LTWAINCAPABILITYCALLBACK Function.
Flags that indicate the capability values to get when enumerating the TWAIN capability. Possible values are:
| Value | Meaning |
|---|---|
| LTWAIN_CAPABILITY_DONTGET | [0] Do not get any capability values. |
| LTWAIN_CAPABILITY_GETCURRENT | [3] Get the current capability value. |
| LTWAIN_CAPABILITY_GETDEFAULT | [4] Get the default capability value. |
| LTWAIN_CAPABILITY_GETVALUES | [5] Get all available capability values. |
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.
| Value | Meaning |
|---|---|
| SUCCESS | The function was successful. |
| ! = SUCCESS | An error occurred. Refer to Return Codes. |
This function must be called after the L_TwainStartCapsNeg is called and before the L_TwainEndCapsNeg is called.
For an example, refer to L_TwainAddCapabilityToFile.