There are two formats of parcel headers. The parcel headers are symbolically defined in the TC2XPH file. The format of the first is:
| Field Name | Offset | Length | Description |
|---|---|---|---|
| PH0FLAVR (FLAVOR-FLAG for COBOL 'flavor' for C, and PL/I) | 00 | 1 bit | A binary zero, indicating this header format. The mnemonic for the bit is PH0FALT ('Tc2ph_Alternate' for C, TPH0_ALTERNATE for PL/I) |
| PH0FLAVR ('flavor' for COBOL, C, and PL/I) | 0.1 | 15 bits | An unsigned integer identifying the type of parcel body. |
| PH0LEN ('length' for C and PL/I) | 02 | 2 bytes | An unsigned integer specifying the length of the parcel, in bytes, including the parcel header and any body. |
The format of the second is:
| Field Name | Offset | Length | Description |
|---|---|---|---|
| PH1FLAVR (FLAVOR-FLAG for COBOL 'flavor' for C and PL/I) | 00 | 1 bit | A binary zero, indicating this header format. The mnemonic for the bit is PH1FALT ('Tc2ph_Alternate' for C, TPH1_ALTERNATE for PL/I) |
| PH1FLAVR ('flavor' for COBOL, C, and PL/I) | 0.1 | 15 bits | An unsigned integer identifying the type of parcel body. |
| PH1FILL1 ('fill1' for COBOL, C, and PL/I) | 02 | 2 bytes | Not used: Set to binary zeroes. |
| PH1LEN ('length' for C and PL/I) | 04 | 4 bytes | An unsigned integer specifying the length of the parcel, in bytes, including the parcel header and any body. |
A response will only contain a parcel with the enlarged header if the APH-response-permitted option was specified and the Teradata Database supports the alternate header for that parcel. Furthermore, parcels whose length is less than or equal to 65535 may use either header format.