Transact

Transact_Fetch
(SWI &4FC07)

Retrieves the whole or a part of a result set (previously built with a Transact_Select) to a client application.

On entry

• R0 = External session ID as returned by Transact_CreateSession;
• R1 = Cursor ID as returned by Transact_Select;
• R2 = Pointer where the engine should store the data (RMA or application workspace);
• R3 = Start of involved zone (offset of the first byte from the beginning of the result set);
• R4 = End of involved zone (offset of the last byte from the beginning of the result set + 1).

On exit

• R1 = Number of bytes successfully copied;
• All other registers are preserved.

Possible errors

• &812B00 Busy (not yet implemented in this release)
• &812B01 Unknown session
• &812B02 Unknown object
• &812B05 Invalid parameters
• &812B04 Not enough memory to service this request
• &812B03 Unknown cursor
• &812B09 No previous SELECT for this cursor
• &812B06 Invalid operation for this cursor mode (FORWARD_ONLY)

Additional notes

• A call to the SWI Transact_Fetch which fetch the last byte of a result set as the cursor mode is FORWARD_ONLY do not trigger a reinit of the cursor (which would allow it to be the object of a subsequent Transact_Select). A call to Transact_AllDone still needs to be done. This may evolve in a future release of the Transact engine;
• The application should ensure that sufficient amount of memory is available to store the data from the result set (at least R4 - R3 bytes should be allocated).
  If some data is missing from the result set, then no error occurs; the client application should check that the returned number of bytes = R4 - R3 upon entry.