RSharedDataClient API ----------------------------------------------------------------------------- Applications use the subsystem via RSharedDataClient class. First, they need to connect to the server by calling Connect() member function.

------------------------------------------------------------------------------ RESERVE FILE SUPPORT ------------------------------------------------------------------------------

This functionality has nothing to do with the rest of SharedData, but is implemented in SharedData server because it is one of the most commonly used servers. The idea is to support transaction-based delete operations to succeed in a full disk situation. SharedData server checks if the free disk space is below the given minimum treshold and if so, reduces the size of a reserve file to free up some disk space. No overhead is caused if there is enough free disk space already. Thus, unless the reserve file is somehow exhausted, the free disk space is guaranteed to be above the given parameter after this call. Of course, the parameter is limited to the maximum size of the reserve file that will be about 140kB.

There are two correct usage patterns represented below, other for synchronous delete operations and other for asynchronous ones.

Note! When the SharedData connection is closed, the server will always assume that the reserve space is no longer required by the corresponding client.

Usage pattern (synchronous delete operation): ------------------------------------------------------------------------------ // iSharedDataClient is connected to the server here.

iSharedDataClient.RequestFreeDiskSpaceLC( KDiskSpaceNeededForDelete );

// Do the delete operation here, the code may leave.

// Do NOT close the SharedData connection here nor delete the // RSharedDataClient object.

CleanupStack::PopAndDestroy() ; // cancels free disk space request ------------------------------------------------------------------------------

Usage pattern (asynchronous delete operation): ------------------------------------------------------------------------------ // iSharedDataClient is connected to the server here.

iSharedDataClient.RequestFreeDiskSpace( KDiskSpaceNeededForDelete );

// Start the asynchronous delete operation here

// Do NOT close the SharedData connection here nor delete the // RSharedDataClient object.

// When the asynchronous request has completed:

iSharedDataClient.CancelFreeDiskSpaceRequest(); ------------------------------------------------------------------------------