IOleContainer::LockContainer - OLE Programmer's Reference (ole.hlp)

IOleContainer::LockContainer

Keeps an embedded object's container running.

HRESULT LockContainer(

BOOL fLock	//Value indicating lock or unlock
);

Parameter
fLock

[in] Specifies whether to lock (TRUE) or unlock (FALSE) a container.

Return Values
S_OK

Container was locked successfully.

E_FAIL

An unspecified error occurred.

E_OUTOFMEMORY

Container could not be locked due to lack of memory.

Comments
An embedded object calls IOleContainer::LockContainer to keep its container running when the object has link clients that require an update. If an end-user selects File Close from the container's menu, however, the container ignores all outstanding LockContainer locks and closes the document anyway.

Notes to Callers
When an embedded object changes from the loaded to the running state, it should call IOleContainer::LockContainer with the fLock parameter set to TRUE. When the embedded object shuts down (transitions from running to loaded), it should call IOleContainer::LockContainer with the fLock parameter set to FALSE.

Each call to LockContainer with fLock set to TRUE must be balanced by a call to LockContainer with fLock set to FALSE. Object applications typically need not call LockContainer; the default handler makes these calls automatically for object applications implemented as .EXEs as the object makes the transition to and from the running state. Object applications not using the default handler, such as DLL object applications, must make the calls directly.

An object should have no strong locks on it when it registers in the Running Object Table, but it should be locked as soon as the first external client connects to it. Therefore, following registration of the object in the Running Object Table, object handlers and DLL object applications, as part of their implementation of IRunnableObject::Run, should call IOleContainer::LockContainer(TRUE) to lock the object.

Notes to Implementors
The container must keep track of whether and how many calls to LockContainer(TRUE) have been made. To increment or decrement the reference count, IOleContainer::LockContainer calls CoLockObjectExternal with a flag set to match fLock.

See Also
CoLockObjectExternal, IRunnableObject::Run

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