62. Remote Procedure Calls (RPC)—Experimental Feature

Remote Procedure Calls, or RPC, is an inter-process communication that allows a computer program to cause a subroutine or procedure to execute in another address space.

RPC has two participants: a client and a service. Under the hood, the client uses a Requester to send requests and receive replies; the service uses a Replier to receive the requests and send the replies.

RPC over DDS uses a function-call style where the client/Requester directly calls the service/Replier by calling the service's functions, abstracting sending the request and receiving the corresponding reply on the client side.

Figure 62.1: RPC Overview

Connext supports both blocking and non-blocking interactions:

• In a blocking (or synchronous) interaction, the client application blocks while waiting for the service’s answer.
• In a non-blocking (or asynchronous) interaction, the client application can proceed with other work, ask if the service’s answer is already available, or wait for the service’s answer.

It is possible for a client to call more than one function at a time, particularly when asynchronous invocations are used.

62.2 RPC Client explains how a client application can use the method provided by the interface to perform both blocking and non-blocking interactions with the service.

Additional resources. In addition to the information in this section, you can find more information and example code here:

• The Connext API Reference HTML documentation contains example code that will show you how to use the API: From the Modules tab, navigate to Programming How-To’s, RPC Tutorial.
• The Connext API Reference HTML documentation also contains the full API documentation for the client-side and server-side APIs. Under the Modules tab, navigate to RTI Connext API Reference, RTI Connext Messaging API Reference, Remote Procedure Call.