ClfsReadPreviousRestartArea function (wdm.h)

The ClfsReadPreviousRestartArea routine reads the previous restart record relative to the current record in a read context.

Syntax

CLFSUSER_API NTSTATUS ClfsReadPreviousRestartArea(
  [in]  PVOID     pvReadContext,
  [out] PVOID     *ppvRestartBuffer,
  [out] PULONG    pcbRestartBuffer,
  [out] PCLFS_LSN plsnRestart
);

Parameters

[in] pvReadContext

A pointer to a read context obtained by a previous call to ClfsReadRestartArea.

[out] ppvRestartBuffer

A pointer to a variable that receives a pointer to the data buffer of the restart record that is read.

[out] pcbRestartBuffer

A pointer to a ULONG-typed variable that receives the size, in bytes, of the buffer pointed to by *ppvRestartBuffer. This is the length of the data buffer of the restart record that is read.

[out] plsnRestart

A pointer to a CLFS_LSN structure that receives the previous LSN of the restart record that was read.

Return value

ClfsReadPreviousRestartArea returns STATUS_SUCCESS if it succeeds; otherwise, it returns one of the error codes defined in Ntstatus.h. If there are no previous restart areas, the return value is STATUS_LOG_START_OF_LOG.

Remarks

For an explanation of CLFS concepts and terminology, see Common Log File System.

For information about reading records from CLFS streams, see Reading Data Records from a CLFS Stream and Reading Restart Records from a CLFS Stream.

Read contexts are not thread-safe. Clients are responsible for serializing access to read contexts.

Clients append restart records to a CLFS log by calling ClfsWriteRestartArea.

With the ReadPreviousLogRestartArea routine, clients can implement a form of fuzzy checkpointing. For example, the checkpoint state could consist of the log records delimited by two or more restart records.

Requirements

See also

CLFS_LSN

ClfsReadRestartArea

ClfsWriteRestartArea