IVssBackupComponents::PrepareForBackup method (vsbackup.h)
The PrepareForBackup method will cause VSS to generate a PrepareForBackup event, signaling writers to prepare for an upcoming backup operation. This makes a requester's Backup Components Document available to writers.
Syntax
HRESULT PrepareForBackup(
[out] IVssAsync **ppAsync
);
Parameters
[out] ppAsync
Doubly indirect pointer to an instance of the IVssAsync interface that is used to determine when the asynchronous operation is complete.
Return value
The following are the valid return codes for this method.
| Value | Meaning |
|---|---|
|
Successfully returned a pointer to an instance of the IVssAsync interface. See IVssAsync::QueryStatus for the error codes returned in the pHrResult parameter. |
|
ppAsync does not point to a valid pointer; that is, it is NULL. |
|
The caller is out of memory or other system resources. |
|
The 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. |
|
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
PrepareForBackup generates a PrepareForBackup event, which is handled by each instance of each writer through the CVssWriter::OnPrepareBackup method.
Before PrepareForBackup can be called, IVssBackupComponents::SetBackupState must be called.
The Backup Components Document can still be modified by writers in their PrepareForBackup event handler (CVssWriter::OnPrepareBackup), and afterward until the generation of a BackupComplete event.
The caller is responsible for releasing the IVssAsync interface.
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::AddComponent
IVssBackupComponents::AddToSnapshotSet