IVssCreateWriterMetadata::AddFilesToFileGroup method (vswriter.h)

Article
10/13/2021

The AddFilesToFileGroup method adds a file set (a specified file or files) to a specified file group component.

Syntax

HRESULT AddFilesToFileGroup(
  [in] LPCWSTR wszLogicalPath,
  [in] LPCWSTR wszGroupName,
  [in] LPCWSTR wszPath,
  [in] LPCWSTR wszFilespec,
  [in] bool    bRecursive,
  [in] LPCWSTR wszAlternateLocation,
  [in] DWORD   dwBackupTypeMask
);

Parameters

[in] wszLogicalPath

Pointer to a null-terminated wide character string containing the logical path (which may be NULL) of the component to which to add the files. For more information, see Logical Pathing of Components.

[in] wszGroupName

Pointer to a null-terminated wide character string containing the name of the file group component. The type of this component must be VSS_CT_FILEGROUP; otherwise, the method will return an error.

[in] wszPath

Pointer to a null-terminated wide character string containing the default root directory of the files to be added.

The directory can be a local directory on the VSS machine, or it can be a file share directory on a remote file server.

UNC paths are supported.

The path can contain environment variables (for example, %SystemRoot%) but cannot contain wildcard characters.

There is no requirement that the path end with a backslash (""). It is up to applications that retrieve this information to check.

[in] wszFilespec

Pointer to a null-terminated wide character string containing the file specification of the files to be included.

A file specification cannot contain directory specifications (for example, no backslashes) but can contain the ? and * wildcard characters.

[in] bRecursive

A Boolean value specifying whether the path specified by the wszPath parameter identifies only a single directory or if it indicates a hierarchy of directories to be traversed recursively. This parameter should be set to true if the path is treated as a hierarchy of directories to be recursed through, or false otherwise.

For information on traversing over mounted folders, see Working with Mounted Folders and Reparse Points.

[in] wszAlternateLocation

Pointer to a null-terminated wide character string containing the alternate path, which actually contains the files to be backed up with this component.

The directory can be a local directory on the VSS machine, or it can be a file share directory on a remote file server.

UNC paths are supported.

Specifying an alternate path is optional; if no alternate path is needed, wszAlternatePath should be NULL.

An alternate path should not be confused with an alternate location mapping.

[in] dwBackupTypeMask

A bitmask of VSS_FILE_SPEC_BACKUP_TYPE enumeration values to indicate if a writer should evaluate the file for participation in a certain type of backup operations.

The default value for this argument is (VSS_FSBT_ALL_BACKUP_REQUIRED | VSS_FSBT_ALL_SNAPSHOT_REQUIRED).

Return value

The following are the valid return codes for this method.

Value	Meaning
S_OK 0x00000000L	The operation was successful.
E_INVALIDARG 0x80070057L	One of the parameter values is not valid, or the caller attempted to add file-group files to a non-file-group component.
E_OUTOFMEMORY 0x8007000EL	The caller is out of memory or other system resources.
VSS_E_INVALID_XML_DOCUMENT 0x80042311L	The XML document is not valid. Check the event log for details. For more information, see Event and Error Handling Under VSS.
VSS_E_NOT_SUPPORTED 0x8004232FL	For express writers, the value of wszAlternatePath must be NULL, and the dwBackupTypeMask bitmask cannot include VSS_FSBT_DIFFERENTIAL_BACKUP_REQUIRED, VSS_FSBT_INCREMENTAL_BACKUP_REQUIRED, or VSS_FSBT_LOG_BACKUP_REQUIRED.
VSS_E_OBJECT_NOT_FOUND 0x80042308L	The specified component 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

Windows 7, Windows Server 2008 R2, Windows Vista, Windows Server 2008, Windows XP and Windows Server 2003: Remote file shares are not supported until Windows 8 and Windows Server 2012. Writers support only local resources—sets of files whose absolute path starts with a valid local volume specification and cannot be a mapped network drive. Therefore, path inputs (wszPath and wszAlternatePath) to AddFilesToFileGroup (after the resolution of any environment variables) must be in this format.

A writer can call this method multiple times to add several sets of files to its file group component. However, you should make sure that the file specifications do not overlap, because a particular file can be specified only once.

The locations from which files are backed up and to which they are restored depends on the values for the root directory defined by wszPath and the alternate path defined by wszAlternatePath.

Note the following when using path information provided by AddFilesToFileGroup:

Restore operations should (if possible) restore files added to a component by AddFilesToFileGroup under the default root directory defined by wszPath.
If an alternate path is not specified (if wszAlternatePath is NULL), the files added to the component will be backed up from the default root directory and restored to the default root directory indicated by wszPath.
If an alternate path is specified (if wszAlternatePath is non-NULL), files added to the component are backed up from the alternate path specified by wszAlternatePath. However, requesters will still use wszPath as the default restoration location.
If the alternate path is defined (wszAlternatePath is non-NULL) and there are files matching the file specification (wszFilespec) in both the alternate path and the default root directory (wszPath), then a backup operation should back up files located under the alternate path, not files located under the default root directory.
Files should be restored to the directory indicated by wszPath unless an alternate location mapping was set by IVssCreateWriterMetadata::AddAlternateLocationMapping and the restore method or restore target requires it.

For more information on backup and restore file locations under VSS, see Non-Default Backup And Restore Locations.

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