IPersistStorage::HandsOffStorage method (objidl.h)

Article
06/29/2021

Instructs the object to release all storage objects that have been passed to it by its container and to enter HandsOff mode.

Syntax

HRESULT HandsOffStorage();

Return value

This method returns S_OK to indicate that the object has entered HandsOff mode successfully.

Remarks

This method causes an object to release any storage objects that it is holding and to enter the HandsOff mode until a subsequent IPersistStorage::SaveCompleted call. In HandsOff mode, the object cannot do anything and the only operation that works is a close operation.

A container application typically calls this method during a full save or low-memory full save operation to force the object to release all pointers to its current storage. In these scenarios, the HandsOffStorage call comes after a call to either OleSave or IPersistStorage::Save, putting the object in HandsOffAfterSave mode. Calling this method is necessary so the container application can delete the current file as part of a full save, or so it can call the IRootStorage::SwitchToFile method as part of a low-memory save.

A container application also calls this method when an object is in Normal mode to put the object in HandsOffFromNormal mode.

While the component object is in either HandsOffAfterSave or HandsOffFromNormal mode, most operations on the object will fail. Thus, the container should restore the object to Normal mode as soon as possible. The container application does this by calling the IPersistStorage::SaveCompleted method, which passes a storage pointer back to the component object for the new storage object.

Notes to Implementers

This method must release all pointers to the current storage object, including pointers to any nested streams and storages. If the object contains nested objects, the container application must recursively call this method for any nested objects that are loaded or running.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	objidl.h