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2.2.3.14.1 adtgHeader

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The adtgHeader sub-message specifies attributes global to the TableGram.

The syntax of an adtgHeader submessage is defined as follows.

 adtgHeader       = adtgTokenHeader
                    adtgHeaderSize
                    adtgSignature
                    adtgVersion
                    adtgByteOrder
                    adtgUnicode
            
 adtgTokenHeader  = %x01
            
 adtgHeaderSize   = BYTE
            
 adtgSignature    = "TG!"
            
 adtgVersion      = adtgMajorVersion adtgMinorVersion
            
 adtgMajorVersion = BYTE
            
 adtgMinorVersion = BYTE
            
 adtgByteOrder    = adtgByteOrderLittleEndian / adtgByteOrderBigEndian
            
 adtgByteOrderLittleEndian   = %x00
 adtgByteOrderBigEndian      = %x01
            
 adtgUnicode = adtgNonUnicodeFormatForMBCS / adtgUnicodeFormatForMBCS
            
 adtgNonUnicodeFormatForMBCS = %x00
 adtgUnicodeFormatForMBCS    = %x01

The definition of a Unicode character is as specified in [UNICODE]. adtgTablegram uses a UTF-16LE encoding.

The fields of an adtgHeader sub-message have the following lengths, types, and meanings:

  • adtgTokenHeader

    Length: 1 byte

    Specifies the beginning of the adtgHeader submessage. The value MUST be set to %x01.

  • adtgHeaderSize

    Length: 1 byte

    The length of the rest of the adtgHeader submessage, in bytes; specifically, the collective length of the adtgSignature, adtgVersion, adtgByteOrder, and adtgUnicode fields, for a fixed value of 7 (%x07).

  • adtgSignature

    Length: 3 bytes

    Specifies the beginning of the adtgTablegram. The value in this field MUST be the 3-byte ASCII string constant "TG!".

  • adtgVersion

    Length: 2 bytes

    Specifies the current version of the protocol being used.<44>

  • adtgByteOrder

    Length: 1 byte

    Specifies the byte order of any multibyte integer values in the adtgTablegram. Applies to WORD, USHORT, LONG, ULONG, WCHAR, and equivalent types.

     Value

     Meaning

    adtgByteOrderLittleEndian

    0x00

    Little-endian

    adtgByteOrderBigEndian

    0x01

    Big-endian (MAY<45> be supported)

  • adtgUnicode

    Length: 1 byte

    Specifies how non-Unicode character data in the rows (found in ColumnData) is encoded for transmission over the wire.<46>

     Value

     Meaning

    adtgNonUnicodeFormatForMBCS

    0x00

    Non-Unicode format

    adtgUnicodeFormatForMBCS

    0x01

    Unicode format