CORBA 2.3.3 Programmer's Guide for C++

The Fw_MD, or framework message data descriptor, class provides an abstraction for a single segment of data and a
get/put recycling factory. Fw_MD objects can be written to and read from, and can be combined to form an abstract
message (Fw_Message object). The message data descriptor object allows a long message to be transmitted and
received in fragments. See also Transfer Event Handler and Event-Handler User.
Class Fw_Message
The Fw_Message, or framework message, class provides an abstraction for a complete message and a get/put recycling
factory. Messages can be written to and read from, and are implemented as a list of Fw_MD objects. See also Transfer
Event Handler and Event-Handler User.
Guardian File-System Event Handlers and Event-Handler Users (Class
NSDEFw_GFS)
The NSDEFw_GFS class enables legacy wrappers to use the Guardian file-system and context-sensitive Pathsend
interfaces. This class is defined in the header file gfsehoss.h.
This class implements client, server, and listener event handlers that use the Guardian file-system protocol in a specific
way. If your legacy clients or servers vary from the semantics provided by this class, you will need to write your own
event handlers.
NSDEFw_GFS consists of the following four main subclasses:
NSDEFw_GFS::Client●
NSDEFw_GFS::Receive_EH●
NSDEFw_GFS::Listener●
NSDEFw_GFS::Server●
Within these subclasses, hashable abstractions are provided for Guardian file-system addresses. A get/put recycling
factory is also included.
Class NSDEFw_GFS::Client
The NSDEFw_GFS::Client class provides classes and methods to support Guardian file-system style communication
with a legacy server. It defines a server's file-system address, an event for tracking I/O completions, and an event handler
that uses this address and event to provide an Fw_Client_EH implementation.
Class NSDEFw_GFS::Receive_EH
The NSDEFw_GFS::Receive_EH class extends the subclass NSDEFw_GFS::Client::EH to provide a
$RECEIVE handler, and translates the semantics of the Guardian READUPDATE, RECEIVEINFO, and REPLY
procedures into an asynchronous Guardian file-system listener and server event-management facility.
Listeners and servers register interest in I/O events associated with their addresses. When READUPDATE produces a
message for an interested party, Receive_EH packages the message in an appropriate event and delivers the event.
Replying to an event invokes REPLY.
Class NSDEFw_GFS::Listener
The NSDEFw_GFS::Listener class provides classes and methods needed by a listener event handler that performs
Guardian file-system style communication with a legacy client in cooperation with a server event handler. It defines a
hashable address abstraction used by listeners to distinguish themselves by subdevice, an event passed from a
Receive_EH object upon receipt of an OPEN message, and an event handler that uses the address abstraction and event