Available in LEADTOOLS Imaging Pro, Vector, Document, and Medical Imaging toolkits. |
#include "lttwn.h"
L_LTTWN_API L_INT L_TwainEnumCapabilities (hSession, pfnCallBack, uFlags, pUserData)
HTWAINSESSION hSession; |
/* handle to an existing TWAIN session */ |
LTWAINCAPABILITYCALLBACK pfnCallBack; |
/* optional callback function */ |
L_UINT uFlags; |
/* optional flags */ |
L_VOID * pUserData; |
/* pointer to more parameters for the callback */ |
Gets the supported capabilities and specified value(s) of each capability.
Parameter |
Description |
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hSession |
Handle to an existing TWAIN session. This handle is obtained by calling the L_TwainInitSession function. |
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pfnCallBack |
Callback function for processing each enumerated capability. Use the function pointer as the value of this parameter. |
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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. |
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uFlags |
Flags that indicate the capability values to get when enumerating the TWAIN capability. Possible values are: |
|
|
Value |
Meaning |
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LTWAIN_CAPABILITY_DONTGET |
[0] Get no capability values. |
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LTWAIN_CAPABILITY_GETCURRENT |
[3] Get the current capability value. |
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LTWAIN_CAPABILITY_GETDEFAULT |
[4] Get the default capability value. |
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LTWAIN_CAPABILITY_GETVALUES |
[5] Get all available capability values. |
pUserData |
Void pointer that you can use to pass one or more additional parameters that the callback function needs. |
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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. |
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If the additional parameters are not needed, you can pass NULL in this parameter. |
Returns
SUCCESS |
The function was successful. |
! = SUCCESS |
An error occurred. Refer to Return Codes. |
Comments
This function must be called after the L_TwainStartCapsNeg is called and before the L_TwainEndCapsNeg is called.
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_TwainStartCapsNeg, L_TwainEndCapsNeg, L_TwainSetProperties, L_TwainGetProperties, L_TwainSetCapability, L_TwainGetCapability, L_TwainInitSession, L_TwainEndSession. |
Topics: |
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Example
For an example, refer to L_TwainAddCapabilityToFile.