There are two formats of parcel headers. Definitions for the parcel headers are located on a release tape as shown below:
For this language . . . | Definitions are located in the. . . |
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IBM Assembler | TDPXPH in library SAMPLIB (z/OS) |
The first format is:
Field Name | Offset | Length | Description |
---|---|---|---|
PH0FLAVR | 00 | 1 bit | A binary zero, indicating this header format. The mnemonic for the bit is PH0FALT |
PH0FLAVR | 0.1 | 15 bits | An unsigned integer identifying the type of parcel body. |
PH0LEN | 02 | 2 bytes | An unsigned integer specifying the length of the parcel, in bytes, including the parcel header and any body. |
The second format is:
Field Name | Offset | Length | Description |
---|---|---|---|
PH1FLAVR | 00 | 1 bit | A binary zero, indicating this header format. The mnemonic for the bit is PH1FALT |
PH1FLAVR | 0.1 | 15 bits | An unsigned integer identifying the type of parcel body. |
PH1FILL1 | 02 | 2 bytes | Not used: Set to binary zeroes. |
PH1LEN | 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 database supports the alternate header for that parcel. Furthermore, parcels whose length is less than or equal to 65535 can use either header format.