IClassFactory::LockServer

Called by the client of a class object to keep a server open in memory, allowing instances to be created more quickly.

HRESULT LockServer(
  BOOL fLock  //Increments or decrements the lock count
);
 

Parameter

fLock

[in] If TRUE, increments the lock count; if FALSE, decrements the lock count.

Return Values

This method supports the standard return values E_FAIL, E_OUTOFMEMORY, and E_UNEXPECTED, as well as the following:

S_OK

The specified object was either locked ( fLock = TRUE) or unlocked from memory ( fLock = FALSE).

Remarks

IClassFactory::LockServer controls whether an object's server is kept in memory. Keeping the application alive in memory allows instances to be created more quickly.

Notes to Callers

Most clients do not need to call this function. It is provided only for those clients that require special performance in creating multiple instances of their objects.

Notes to Implementers

If the lock count is zero, there are no more objects in use, and the application is not under user control, the server can be closed. One way to implement IClassFactory::LockServer is to call CoLockObjectExternal.

The process that locks the object application is responsible for unlocking it. Once the class object is released, there is no mechanism that guarantees the caller connection to the same class later (as in the case where a class object is registered as single-use). It is important to count all calls, not just the last one, to IClassFactory::LockServer, because calls must be balanced before attempting to release the pointer to the IClassFactory interface on the class object or an error results. For every call to LockServer with fLock set to TRUE, there must be a call to LockServer with fLock set to FALSE. When the lock count and the class object reference count are both zero, the class object can be freed.

Requirements

  Windows NT/2000: Requires Windows NT 3.1 or later.
  Windows 95/98: Requires Windows 95 or later.
  Header: Declared in unknwn.h.

See Also

CoLockObjectExternal