This interface contains procedures to control the Shared Object RunTime system. Each process must call these routines to set up the shared object system. In particular, the runtime system needs to know which process is its default sequencer.

A sequencer coordinates sequencing and distribution of object updates. To sequence the updates, it takes the update requests it receives from copies of the shared objects, serializes them, assigned each a sequence number and sends them back to all copies. This is how the system ensures that all copies of the objects have all updates applied to them in the same order.

Each object has one sequencer that handles its updates. By default, each machine has a sequencer that handles all the objects created on it. If the sequencer for the object is not the default sequencer for that machine, the sequencer will take care of fowarding messages to the appropriate sequencer. The default sequencer is set using the SetDfltSequencer() procedure. If the return value of LocalSpace() is passed to SetDfltSequencer(), this process becomes a sequencer.

INTERFACE SharedObjRT;

IMPORT ObjectSpace, Text, SharedObj, Thread;

PROCEDURE LocalSpace(): ObjectSpace.T;

Each space (running Modula-3 process) has its own local space object. This object is used to communicate with other spaces to control the shared object system. No routines in the ObjectSpace.T object that should be called by the user.

PROCEDURE SetDfltSequencer(seq: ObjectSpace.T) RAISES {SharedObj.Error};

PROCEDURE ExportSpace(name: Text.T) RAISES {SharedObj.Error, Thread.Alerted};

PROCEDURE ImportSpace (host: Text.T; name: Text.T): ObjectSpace.T
  RAISES {SharedObj.Error, Thread.Alerted};

PROCEDURE DebugLevel(p: INTEGER);

PROCEDURE FlushIncomingUpdates() RAISES {Thread.Alerted};

PROCEDURE FlushQueuedUpdates() RAISES {Thread.Alerted};

END SharedObjRT.