IRootStorage  2Y7X_F8

The IRootStorage interface contains a single method that switches a storage object to a different underlying file and saves the storage object to that file. The save operation occurs even with low memory conditions and uncommitted changes to the storage object. A subsequent call to IStorage::CommitW250T5 is guaranteed to not consume any additional memory.

When to Implement

Storage objects that are based on a file should implement IRootStorage in addition to the IStorageFS1VT1 interface. For storage objects that are not file-based, this interface is not necessary.

OLE provides an implementation of a storage object, including the IRootStorage interface, as part of its compound file implementation.

When to Use

The primary use for the IRootStorage interface is to save a storage object to a file during low memory conditions. Typically, the container application calls the IRootStorage interface to switch to a new file.

If you have an IStorage pointer to a compound file object, you can call IStorage::QueryInterface with IID_IRootStorage to obtain a pointer to the IRootStorage interface.

Methods in Vtable Order

See Also