IVssExamineWriterMetadata::GetAlternateLocationMapping method (vsbackup.h)

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The GetAlternateLocationMapping method obtains a specific alternate location mapping of a file set.

Syntax

HRESULT GetAlternateLocationMapping(
  [in]  UINT           iMapping,
  [out] IVssWMFiledesc **ppFiledesc
);

Parameters

[in] iMapping

Index of a particular mapping. The value of this parameter is an integer from 0 to n–1 inclusive, where n is the total number of alternate location mappings associated with a given writer. The value of n is returned by IVssExamineWriterMetadata::GetRestoreMethod.

[out] ppFiledesc

Doubly indirect pointer to an IVssWMFiledesc object containing the alternate location mapping information.

Return value

The following are the valid return codes for this method.

Value Meaning
S_OK
 Successfully returned a pointer to an IVssWMFiledesc interface.
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.
VSS_E_OBJECT_NOT_FOUND
 The specified alternate location mapping does not exist.
VSS_E_UNEXPECTED
 Unexpected error. The error code is logged in the error log file. For more information, see Event and Error Handling Under VSS.

Windows Server 2008, Windows Vista, Windows Server 2003 and Windows XP:  This value is not supported until Windows Server 2008 R2 and Windows 7. E_UNEXPECTED is used instead.

Remarks

The value returned by IVssExamineWriterMetadata::GetAlternateLocationMapping should not be confused with that returned by IVssComponent::GetAlternateLocationMapping.

IVssComponent::GetAlternateLocationMapping is the alternate location to which a file was restored.

IVssExamineWriterMetadata::GetAlternateLocationMapping is the alternate location mapping to which a file may be restored if necessary.

A file should always be restored to its alternate location mapping if either of the following is true:

  • The restore method (set at backup time) is VSS_RME_RESTORE_TO_ALTERNATE_LOCATION.
  • Its restore target was set (at restore time) to VSS_RT_ALTERNATE.
In either case, if no valid alternate location mapping is defined, this constitutes a writer error.

A file may be restored to an alternate location mapping if either of the following is true:

  • The restore method is VSS_RME_RESTORE_IF_NOT_THERE and a version of the file is already present on disk.
  • The restore method is VSS_RME_RESTORE_IF_CAN_REPLACE and a version of the file is present on disk and cannot be replaced.
Again, if no valid alternate location mapping is defined, this constitutes a writer error.

An alternate location mapping is used only during a restore operation and should not be confused with an alternate path, which is used only during a backup operation.

The caller is responsible for calling IUnknown::Release to release the resources of the returned IVssWMFiledesc object.

Requirements

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

See also

IVssBackupComponents::AddAlternativeLocationMapping

IVssComponent::GetAlternateLocationMapping

IVssExamineWriterMetadata

IVssExamineWriterMetadata::GetRestoreMethod

IVssWMFiledesc