nf-txlogpub-ilog-readrecordprefix.md

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NF:txlogpub.ILog.ReadRecordPrefix	ILog::ReadRecordPrefix (txlogpub.h)	Reads an initial part of a record from the log.	ILog interface [COM] ReadRecordPrefix method ILog.ReadRecordPrefix ILog::ReadRecordPrefix ReadRecordPrefix ReadRecordPrefix method [COM] ReadRecordPrefix method [COM] ILog interface _com_ilog_readrecordprefix com.ilog_readrecordprefix txlogpub/ILog::ReadRecordPrefix	com\ilog_readrecordprefix.htm	com	4a2b8529-b342-4491-a7ce-db4150223682	12/05/2018	ILog interface [COM],ReadRecordPrefix method, ILog.ReadRecordPrefix, ILog::ReadRecordPrefix, ReadRecordPrefix, ReadRecordPrefix method [COM], ReadRecordPrefix method [COM],ILog interface, _com_ilog_readrecordprefix, com.ilog_readrecordprefix, txlogpub/ILog::ReadRecordPrefix	txlogpub.h		Windows	Windows XP [desktop apps only]	Windows Server 2003 [desktop apps only]					Txlogpub.idl								Windows			19H1	ILog::ReadRecordPrefix txlogpub/ILog::ReadRecordPrefix	c++	APIRef kbSyntax	COM	Txlogpub.h	ILog.ReadRecordPrefix

ILog::ReadRecordPrefix

-description

Reads an initial part of a record from the log.

-parameters

-param lsnToRead [in]

The LSN of the record to be read.

-param plsnPrev [in, out]

A pointer to the LSN of the previous record (the record immediately preceding the record to read). You may pass NULL if the LSN of the previous record is not needed. This parameter is 0 if there is no previous record in the log or if an error occurs.

-param plsnNext [in, out]

A pointer to the LSN of the next record (the record immediately following the record to read). You may pass NULL if the LSN of the next record is not needed. This parameter is MAXLSN (0x7FFFFFFFFFFFFFFF) if there is no next record in the log. This parameter is 0 if an error occurs.

-param pbData [out]

A pointer to a buffer into which the record data is to be read.

-param pcbData [in, out]

A pointer to a variable that contains the size in bytes of the buffer on input, and will contain the size in bytes of the record data read on return.

-param pcbRecord [out]

A pointer to a variable that will contain the size in bytes of the entire record on return. You may pass NULL if the size of the entire record is not needed.

-returns

This method can return the following values, as well as other HRESULT values.

Return code	Description
S_OK	The record was successfully read from the log.
XACT_E_INVALIDLSN	lsnToRead is outside of the current limits of the log. See ILog::GetLogLimits.
E_INVALIDARG	lsnToRead is within the current limits of the log, but it is not the LSN of a record in the log.

-remarks

Although records appended to the log using ILog::AppendRecord may be concatenated from multiple BLOBs, ReadRecordPrefix returns the record as a single opaque blob of data. ILog provides no method to extract individual BLOBs from the record. It is the responsibility of the caller to parse the data in records returned by ReadRecordPrefix.

-see-also

ILog