# KVGetSubFileMetaArg

This structure defines the metadata tags whose values are retrieved by fpGetSubFileMetaData(). This structure is defined in `kvxtract.h`.

    typedef struct  tag_KVGetSubFileMetaArg
    {
        KVStructHeader;
        int                index;
        int                metaNameCount;
        KVMetaName        *metaNameArray;
        KVCharSet          srcCharset;
        KVCharSet          trgCharset;
        int                isMSBLSB;
    }
    KVGetSubFileMetaArgRec, *KVGetSubFileMetaArg;

## Member Descriptions

`KVStructHeader` | The KeyView version of the structure. See KVStructHead.
`index` | The index number of the subfile for which metadata is extracted.
`metaNameCount` | The number of metadata fields to be extracted.
`metaNameArray` | A pointer to the KVMetaName structure that contains an array of metadata tags whose values are retrieved.
`srcCharset` | Specifies the source character set of the metadata when the format’s reader cannot determine the character set. The character sets are enumerated in `KVCharSet` in `kvcharset.h`. See Discussion.
`trgCharset` | The target character set of the extracted metadata. The character sets are enumerated in `KVCharSet` in `kvcharset.h`.
`isMSBLSB` | This flag indicates whether the byte order for Unicode text is Big Endian (MSBLSB) or Little Endian (LSBMSB).

## Discussion

- If the character set is detected and is also specified in `srcCharset`, the detected character set is overridden by the specified character set. If the source character set is not detected and is not specified, character set conversion does not occur. The section Document Readers lists the formats for which the source character set can be determined.

- KeyView can extract a predefined set of common subfile metadata fields for all mail formats, and can extract all metadata from EML, MBX, MIME, NSF, ICS, and DXL files. To extract the common metadata fields, pass in `0` for `metaArg->metaNameCount`, and `NULL` for `metaArg->metaNameArray`. To extract all metadata, pass in `-1` for `metaArg->metaNameCount` and `NULL` for `metaArg->metaNameArray`. For more information, see Extract Mail Metadata.

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