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IVssBackupComponentsSetPreviousBackupStamp Method

Sets the backup stamp of an earlier backup operation, upon which a differential or incremental backup operation will be based.

The method can be called only during a backup operation.

Namespace: Alphaleonis.Win32.Vss
Assembly: AlphaVSS.Common (in AlphaVSS.Common.dll) Version: 1.3.0.0 (1.3.0.0)
Syntax
void SetPreviousBackupStamp(
	Guid writerId,
	VssComponentType componentType,
	string logicalPath,
	string componentName,
	string previousBackupStamp
)

Parameters

writerId
Type: SystemGuid
Writer identifier.
componentType
Type: Alphaleonis.Win32.VssVssComponentType
Type of the component.
logicalPath
Type: SystemString

The logical path of the component. For more information, see Logical Pathing of Components.

The value of the string containing the logical path used here should be the same as was used when the component was added to the backup set using AddComponent(Guid, Guid, VssComponentType, String, String).

The logical path can be .

There are no restrictions on the characters that can appear in a non-null logical path.

componentName
Type: SystemString

The name of the component.

The value of the string should not be , and should contain the same component as was used when the component was added to the backup set using AddComponent(Guid, Guid, VssComponentType, String, String).

previousBackupStamp
Type: SystemString
The backup stamp to be set.
Exceptions
ExceptionCondition
ArgumentNullExceptionOne of the arguments that cannot be was
ArgumentExceptionOne of the parameter values is not valid.
OutOfMemoryExceptionOut of memory or other system resources.
SystemExceptionUnexpected VSS system error. The error code is logged in the event log.
VssBadStateExceptionThe backup components object is not initialized, this method has been called during a restore operation, or this method has not been called within the correct sequence.
VssObjectNotFoundExceptionThe backup component does not exist.
VssInvalidXmlDocumentExceptionThe XML document is not valid. Check the event log for details.
Remarks

This method should be called before PrepareForBackup.

Only requesters can call this method.

The backup stamp set by SetPreviousBackupStamp(Guid, VssComponentType, String, String, String) applies to all files in the component and any nonselectable Subcomponents it has.

Requesters merely store the backup stamps in the Backup Components Document. They cannot make direct use of the backup stamps, do not know their format, and do not know how to generate them.

Therefore, the value set with SetPreviousBackupStamp(Guid, VssComponentType, String, String, String) should either be retrieved from the stored Backup Components Document of an earlier backup operation (using BackupStamp for the correct component), or from information stored by the requester into its own internal records.

A writer will then obtain this value (using IVssComponent::GetPreviousBackupStamp) and using it will be able to mark the appropriate files for participation in an incremental or differential backup.

See Also