Desktop Communication Protocol (DCOP) was an inter-process communication (IPC)

daemon Daimon or Daemon (Ancient Greek: , "god", "godlike", "power", "fate") originally referred to a lesser deity or guiding spirit such as the daimons of ancient Greek religion and mythology and of later Hellenistic religion and philosophy. The wo ...

KDE KDE is an international free software community that develops free and open-source software. As a central development hub, it provides tools and resources that allow collaborative work on this kind of software. Well-known products include the ...

used in K Desktop Environment 3. The design goal for the protocol was to allow

applications Application may refer to: Mathematics and computing * Application software, computer software designed to help the user to perform specific tasks ** Application layer, an abstraction layer that specifies protocols and interface methods used in a c ...

to interoperate, and share complex tasks. Essentially, DCOP was a ‘remote control’ system, which allowed applications or scripts to enlist the help of other applications. DCOP is built on top of the X11 Inter-Client Exchange protocol. DCOP continues to be used by the K Desktop Environment 3-fork Trinity Desktop Environment. DCOP was replaced by

D-Bus In computing, D-Bus (short for "Desktop Bus") is a message-oriented middleware mechanism that allows communication between multiple processes running concurrently on the same machine. D-Bus was developed as part of the freedesktop.org project, ...

, a message bus system heavily influenced by the DCOP and standardized by freedesktop.org, in

KDE Software Compilation 4 KDE Software Compilation 4 (KDE SC 4) was the only series of the so-called KDE Software Compilation (short: KDE SC), first released in January 2008 and the last release being 4.14.3 released in November 2014. It was the follow-up to K Desktop En ...

and later.

DCOP model

DCOP implements the

client–server model The client–server model is a distributed application structure that partitions tasks or workloads between the providers of a resource or service, called servers, and service requesters, called clients. Often clients and servers communicate ov ...

, where each application using DCOP is a client and communicates with other clients through the DCOP server. DCOP server functions like a traffic director, dispatching messages/calls to the proper destinations. All clients are peers of each other. Two types of actions are possible with DCOP: "send and forget" messages, which do not block, and "calls," which block waiting for some data to be returned. Any data that will be sent is serialized (also referred to as '' marshalling'' in

CORBA The Common Object Request Broker Architecture (CORBA) is a standard defined by the Object Management Group (OMG) designed to facilitate the communication of systems that are deployed on diverse platforms. CORBA enables collaboration between sy ...

speak) using the built-in QDataStream operators available in all of the Qt classes. There is also a simple IDL-like compiler available (dcopidl and dcopidl2cpp) that generates stubs and skeletons. Using the dcopidl compiler has the additional benefit of

type safety In computer science, type safety and type soundness are the extent to which a programming language discourages or prevents type errors. Type safety is sometimes alternatively considered to be a property of facilities of a computer language; that i ...

. There is a command-line tool called ‘dcop’ (note the lower-case letters) that can be used for communication with the applications from the shell. ‘kdcop’ is a GUI tool to explore the interfaces of an application.

External links

DCOP Documentation
{{KDE Inter-process communication KDE Platform Software that uses Qt

DCOP model

See also

External links