Usage Notes
The Using Data Length field has three meanings relating to the following:
- Contents of the request string
- Contents of the data string
- Length in bytes of the data string
| Language | Variable Name |
|---|---|
| COBOL: | DBCAREA-USING-DATA-LEN |
| C: DBCAREA.H: | using_data_len |
| Routine | Action Taken |
|---|---|
| DBCHINI: | writes |
| DBCHCL: | reads (IRQ) |
| Used by | Action Taken |
|---|---|
| application program | writes |
- If Using Data Length is zero:
- No USING clause is to be in the request string.
- No data string is to accompany the request (thus neither Using Data Pointer nor Use Presence Bits contain meaningful information).
- The length of the non-existent data string is zero.
- If Using Data Length is non-zero:
- A USING clause begins the request string.
- A data string accompanies the request (thus Using Data Pointer and Use Presence Bits contain meaningful information).
- The length of the data string (including the bytes containing presence bits, if any) in bytes is provided as the value of Using Data Length.
Before calling DBCHCL for the Initiate Request function and if the request contains a USING modifier, the database application program must build a data string. The data string must contain the data described by the USING modifier.
The data string is placed in Using Data Length.
Because DBCHCL does not parse the request string, the application program must check whether the request string contains a USING clause and to set Using Data Length appropriately.