# KVGetExtractInterface()

This function is the entry point to obtain the file extraction functions. It supplies pointers to the file extraction functions, and in the case of out-of-process mode starts the `kvoop.exe` server and initializes out-of-process extraction services. When `KVGetExtractInterface()` is called, it assigns the function pointers in the structure `KVExtractInterface` to the functions described in this section.

## Syntax

    int pascal KVGetExtractInterface (
        void                    *pContext,
        KVExtractInterface       pIextract);

## Arguments

`pContext` | A pointer returned from `fpInit()` or `fpInitWithLicenseData()`.
`pIextract` | A pointer to the KVExtractInterface structure, which contains function pointers that `KVGetExtractInterface`() assigns to all other file extraction functions. Before you initialize the `KVExtractInterface` structure, use the macro `KVStructInit` to initialize the `KVStructHead` structure.

## Returns

- If the call is successful, the return value is `KVERR_Success`.

- If the call is not successful, the return value is an error code.

## Example

    fpKVGetExtractInterface =
    (int (pascal *)( void *, KVExtractInterface))myGetProcAddress(hKVFilter, (char*)"KVGetExtractInterface");
    /*Initialize file extraction interface structure using KVStructInit*/
    KVStructInit(&extractInterface);
    /* Retrieve file extraction interface */
    error = (*fpKVGetExtractInterface)(pFilter,&extractInterface))

## Discussion

You can define only one extraction structure for one context pointer. For example, the following is not allowed:

    fpInit()
       KVGetExtractInterface(pFilter, &extractInterface1)

       fpOpenFile()
       fpGetMainFileInfo()
       fpGetSubFileInfo()
       fpExtractSubFile
       fpGetSubFileMetadata()
       fpFilterFile()
       fpCloseFile()
       ...

       KVGetExtractInterface(pFilter, &extractInterface2)
       fpOpenFile()
       fpGetMainFileInfo()
       fpGetDocInfoFile()
       fpGetOLESummaryInfoFile()
       fpFilterFile()
       fpCloseFile()
       ...
    fpShutdown()

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