| 1 | Number of data bytes read | Output | Binary(4) |
| 2 | Input buffer handle | Input | Binary(4) |
| 3 | Command buffer handle | Input | Binary(4) |
| 4 | Low-level environment handle | Input | Binary(4) |
| 5 | Error code | I/O | Char(*) |
| Number of data bytes read | Output | Binary(4) |
The Read Screen (QsnReadScr) API reads the contents of the entire screen without requiring an AID-generating key to be pressed. The command buffer handle or input buffer handle parameter must be specified as described in Put Input Command (QsnPutInpCmd) API.
The data returned consists of the contents of the entire display, including the attributes. No formatting or conversion is done. The data will be available in the data portion of the input buffer. The result of this operation can be queried using the Retrieve Length of Data in Input Buffer (QsnRtvDtaLen) API and the Retrieve Pointer to Data in Input Buffer (QsnRtvDta) API.
This command corresponds directly to the 5250 Read Screen command.
None
The same restrictions apply as for the Read Immediate (QsnReadImm) API. In addition, this command cannot be issued if the control unit supports ideographic data types. A CPFA306 error occurs if an attempt is made to issue this command to a control unit that supports ideographic data types.
The variable that contains the number of data bytes returned after the QsnReadScr API has completed if a direct operation is specified. The parameter is not modified for an indirect operation and the value remains unchanged from whatever was passed.
A handle for the input buffer that receives the result of the input operation if a direct operation is specified. The result can be queried using the input buffer query operations. See Retrieve Pointer to Field Data (QsnRtvFldDta) API and Retrieve Length of Field Data in Buffer (QsnRtvFldDtaLen) API.
A handle for the command buffer in which to store the command.
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.
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.
This API returns the value for the number of data bytes read parameter if a direct operation was specified, or -1 if an error occurs during processing. If this is an indirect operation, this API returns zero if successful, or -1 otherwise.
| 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. |
| CPFA302 E | Command buffer or input buffer parameters required. |
| CPFA304 E | Data-stream error &1 reported for screen I/O operation. |
| CPFA305 E | Cannot add operation to command buffer. |
| CPFA309 E | Invalid cursor position in command buffer. |
| CPFA313 E | Command buffer already contains an input operation. |
| CPFA331 E | Buffer handle incorrect. |
| CPFA334 E | Low level environment handle incorrect. |
| CPFA343 E | Output operation not done. |
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