IVssComponent::GetPreviousBackupStamp method (vswriter.h)

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The GetPreviousBackupStamp method returns a previous backup stamp loaded by a requester in the Backup Components Document. The value is used by a writer when deciding if files should participate in differential or incremental backup operation.

Either a writer or a requester can call this method.

Syntax

HRESULT GetPreviousBackupStamp(
  [out] BSTR *pbstrBackupStamp
);

Parameters

[out] pbstrBackupStamp

Pointer to a string containing the time stamp of a previous backup so that a differential or incremental backup can be correctly implemented.

Return value

The following are the valid return codes for this method.

Value Meaning
S_OK
 Successfully returned the attribute value.
S_FALSE
 No previous backup time stamp has been set.
E_INVALIDARG
 One of the parameter values is not valid.
E_OUTOFMEMORY
 The caller is out of memory or other system resources.
VSS_E_INVALID_XML_DOCUMENT
 The XML document is not valid. Check the event log for details. For more information, see Event and Error Handling Under VSS.

Remarks

For more information about backup stamps, see Writer Role in Backing Up Complex Stores and Requester Role in Backing Up Complex Stores.

The caller should free the memory held by the pbstrBackupStamp parameter by calling SysFreeString.

If there is no previous backup time stamp, GetPreviousBackupStamp returns S_FALSE.

The string returned refers to all files in the component and any nonselectable subcomponents it has.

The backup stamp retrieved by GetPreviousBackupStamp is set by a requester using IVssBackupComponents::SetPreviousBackupStamp.

Typically, the string used to set the value found by GetPreviousBackupStamp was retrieved from a stored Backup Components Document or was stored by the requester as part of its own internal records.

Requirements

Requirement Value
Minimum supported client Windows XP [desktop apps only]
Minimum supported server Windows Server 2003 [desktop apps only]
Target Platform Windows
Header vswriter.h (include Vss.h, VsWriter.h)
Library VssApi.lib

See also

IVssBackupComponents::SetPreviousBackupStamp

IVssComponent