Client:
    char request[RequestSize];
    char reply[ReplySize]

    // ..compute..

    // Put the request into the buffer.

    // Send the buffer to the server.
    write(output, request, RequestSize);
	
    // Wait for response.
    read(input, reply, ReplySize);
	
    // ..compute..

Server:
    char request[RequestSize];
    char reply[ReplySize];

    // Loop waiting for requests.
    while (1) {
        // Read incoming command.
        read(input, request, RequestSize);

        // Do operation.

        // Send result.
        write(output, reply, ReplySize);
    }