Cpl::Itc Namespace Reference

The Itc namespace provides classes for message based Inter Thread Communications (ITC) as well as Event Flags. More...

Detailed Description

The Itc namespace provides classes for message based Inter Thread Communications (ITC) as well as Event Flags.

The ITC message mechanism has the following characteristics:

o The ITC model is a client-server model, where client(s) send messages
  to server(s).  

o Messages can be sent asynchronously or synchronously.

o Data flow between clients and server can be uni-directional or 
  bi-directional (determined by the application). Because this is
  inter-thread communication, data can be shared via pointers (if
  desired) since Clients and Servers share the same address space.

o Data is shared between clients and server using the concept of a
  'payload'.  In addition, a convention of ownership is used to
  provide thread-safe  access to the payload.
  - A client initially owns the payload, i.e. can access the data
    in the payload without the use of critical sections.
  - When a client sends (or posts) a message, there is implicit transfer
    of ownership of the payload.  After sending the message, the client
    is obligated to NOT access the payload contents.
  - When a server received a message, the server now 'owns' the payload
    and can access the data in the payload without the use of critical
    sections.
  - When a server 'returns' a message, there is implicit transfer of
    ownership of the payload back to the client. After returning the
    message, the server is obligated to NOT access the payload contents.

o NO dynamic memory is used.  Clients are responsible for providing all
  of the memory required for the individual message(s).
  - This translate to no hard limits to the number of messages a server
    can receive.  It also means that the application does NOT have to
    worry about 'overflowing' message queues and/or mailboxes.
  - Another side effect of the memory paradigm is that there is NO 
    'broadcast' messages.

o 100% type safe. Messages and payloads are handled and dispatched with 
  NO typecasting required.

The ITC Event Flags mechanism has the following characteristics:

o Each thread supports up to N unique event flags. Event flags are not 
  unique across threads, i.e. The semantics associated with event flag1 
  for Thread A, is independent/different than the semantics associated with 
  event flag1 for Thread B.

o An individual event flags can be viewed as binary semaphore with respect 
  to be signaled/waiting (though waiting is done on the thread's entire set 
  of event flags).

o A thread (runnable object) can wait for at least one event to be signaled.
  When the thread is waiting on event(s) and it is then signaled - all of
  Events that were in the signaled state when the thread was unblock are
  cleared.

Classes
class	AsyncReturnHandler
	This class implements an asynchronous ReturnHandler. More...
class	AtomicApi
	This abstract class provides an interface to allow a client to call the server synchronously to have the server invoke the client's atomic operation. More...
class	AtomicCallback
	This abstract class defines a call-back interface that clients use to issue multiple service requests as a single "atomic" operation. More...
class	AtomicRequest
	This concrete class define the 'Atomic' Message request that allows a client to invoke multiple operation on a server/service as one single atomic operation. More...
class	AtomicResponse
	This abstract class define response message types for a set of ITC services. More...
class	AtomicSync
	This concrete class provides the ITC wrapper implementation for calling the "Atomic Api" synchronously. More...
class	CloseApi
	This abstract class defines an close interface. More...
class	CloseRequest
	This abstract class define message types and payloads for a set of ITC services. More...
class	CloseResponse
	This abstract class define response message types for a set of ITC services. More...
class	CloseSync
	This partially concrete class implements the synchronous ITC close call for the CloseApi. More...
class	Mailbox
	This mailbox class implements an Inter Thread Communications message queue. More...
class	MailboxServer
	This class collects the common functions of a generic server providing a mailbox and Event loop. More...
class	Message
	This abstract class defines the operations for an ITC message. More...
class	NullReturnHandler
	This class implements a Null ReturnHandler. More...
class	OpenApi
	This abstract class defines an open interface. More...
class	OpenRequest
	This abstract class define message types and payloads for a set of ITC services. More...
class	OpenResponse
	This abstract class define response message types for a set of ITC services. More...
class	OpenSync
	This partially concrete class implements the synchronous ITC open call for the OpenApi. More...
class	PeriodicScheduler
	This class extends the Cpl::Itc::MailboxServer class to add periodic scheduling to an event based 'thread'. More...
class	PostApi
	This abstract class represents the interface used to send messages to a mailbox. More...
class	RequestMessage
	This template class represents a service request message to a particular server. More...
class	ResponseMessage
	This template class represents a client response message, which is posted to the client's mailbox after the corresponding server request message is returned to the client via the server message returnToSender interface. More...
class	ReturnHandler
	This abstract class represents the action that is executed by a server thread in response to the server completing the operation requested by the SrvMsg, when the server invokes the returnToSender() operation of the message. More...
class	SAP
	This concrete template class represents the interface to a ITC Service Access Point (SAP). More...
class	ServiceMessage
	This class represents a defined message, which is posted to a mailbox-server as a request. More...
class	SyncReturnHandler
	This class implements a synchronous ReturnHandler. More...