Usage Notes
The Using Data Pointer field specifies the address of the data string that is referred to by the USING clause in the request string. DBCHCL does not parse the request string. It is the application program’s responsibility to be certain that a data string exists and that it is pointed to by Using Data Pointer if a USING clause is in the request string.
| Language | Variable Name |
|---|---|
| COBOL: | DBCAREA-USING-DATA-PRT |
| C: DBCAREA.H: | using_data_ptr |
| Routine | Action Taken |
|---|---|
| DBCHINI: | writes |
| DBCHCL: | reads (IRQ) |
| Used by | Action Taken |
|---|---|
| application program | writes |
- If the data cannot contain null values, the application program sets Use Presence Bits to 'N' in the DBCAREA.
- If the data can contain null values, the application program inserts bytes containing indicator bits (one per column) at the front of the data string and sets Use Presence Bits to 'Y'. See Use Presence Bits.
The application program must place the address of the first byte of presence bits or the first byte of the data string, if there are no presence bits, in Using Data Pointer.
If there is no USING clause in the request string, be certain that Using Data Length is set to zero; otherwise, whatever value is in Using Data Pointer is used as if it were a real address and may cause unpredictable errors.