Roll Down (QsnRollDown) API
Required Parameter Group:
1 | Number of lines to roll | Input | Binary(4) |
2 | Top row of roll area | Input | Binary(4) |
3 | Bottom row of roll area | Input | Binary(4) |
Omissible Parameter Group:
4 | Command buffer handle | Input | Binary(4) |
5 | Low-level environment handle | Input | Binary(4) |
6 | Error code | I/O | Char(*) |
Returned Value:
Return code | Output | Binary(4) |
Default Public Authority: *USE
Service Program: QSNAPI
Threadsafe: No
The Roll Down (QsnRollDown) API rolls the screen down a given number of lines within the roll area specified. The following conditions cause a CPFA315 error to occur:
- A top row of zero
- A bottom row greater than the number of display lines
- A top row greater than or equal to the bottom row
- A roll area greater than the bottom row minus the top row
This API corresponds directly to the 5250 Roll command. See the 5250 data stream documentation for details.
Restrictions
The following considerations apply to the QsnRollDown API:
- Lines vacated due to a roll are not cleared to nulls.
- The command does not change the format table, and so, should be avoided when it could produce discrepancies between the format table and the display.
- Data rolled out of the roll area are lost.
Authorities and Locks
None.
Required Parameter Group
- Number of lines to roll
- INPUT; BINARY(4)
The number of lines to roll the designated area down by.
- Top row of roll area
- INPUT; BINARY(4)
The line number defining the top line of the area that will participate in the roll.
- Bottom row of roll area
- INPUT; BINARY(4)
The line number defining the bottom line of the area that will participate in the roll.
Omissible Parameter Group
- Command buffer handle
- INPUT; BINARY(4)
If this parameter is omitted or specified as 0, this is a direct operation and the screen is rolled down immediately. Otherwise, this is an indirect operation and the command is stored in the command buffer without an I/O operation taking place.
- Low-level environment handle
- INPUT; BINARY(4)
The low-level environment that the operation applies to. If this parameter is omitted or given with a value of zero, the default low-level environment is used.
- Error code
- I/O; CHAR(*)
The structure in which to return error information. For the format of the structure, see Error code parameter. If this parameter is omitted, diagnostic and escape messages are issued to the application.
Returned Value
- Return code
- OUTPUT; BINARY(4)
A return code indicating the result of the operation. The value returned will be 0 if the operation was successful, or -1 otherwise.
Error Messages
Message ID | Error Message Text |
---|---|
CPF24B4 E | Severe error while addressing parameter list. |
CPF3CF1 E | Error code parameter not valid. |
CPF3CF2 E | Error(s) occurred during running of &1 API. |
CPFA301 E | Command buffer is full. |
CPFA303 E | Error occurred for screen I/O operation. |
CPFA304 E | Data-stream error &1 reported for screen I/O operation. |
CPFA305 E | Cannot add operation to command buffer. |
CPFA315 E | Roll parameters not valid. |
CPFA31E E | Required parameter &1 omitted. |
CPFA331 E | Buffer handle incorrect. |
CPFA334 E | Low level environment handle incorrect. |
CPFA343 E | Output operation not done. |
CPFA344 E | The file &2 in library &3 is not valid. |
CPFA345 E | The invite active flag is not valid. |
API introduced: V2R3
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