Using the BEGINLOG and ENDLOG Intrinsics

To take full advantage of the data protection of User Logging, a logical transaction should be defined for the application. All actions that must be performed together for data to be in a consistent state should be included. In case the transaction is interrupted, the beginning and end of each transaction should be marked allowing fully and partially completed transactions to be identified.

The BEGINLOG intrinsic writes a special record to the logfile, marking the beginning of a logical transaction. When BEGINLOG is used, the User Logging memory buffer is flushed to ensure the record gets to the logfile. A BEGINLOG record with no data can be written to mark the beginning of a transaction, or data may be included (refer to the WRITELOG intrinsic). Including data allows the user to include information about the entire logical transaction, or to mark the beginning of the logical transaction and write the first log record with a single intrinsic call.

	NOTE: The WRITELOG intrinsic may be used to write logging records for each action within the transaction.

ENDLOG contains the same information as BEGINLOG except it marks the end of a transaction. ENDLOG may be called with or without data, and it flushes the User Logging memory buffer to ensure the record gets to the logfile.

BEGINLOG and ENDLOG pairs may be nested within other pairs and may be called any number of times. User Logging does not keep track of matching BEGINLOGs and ENDLOGs; it is the user's responsibility to ensure they are properly matched. If they are not matched, they will not be useful in recovery.