V    Metadata is data that describes other data. Cryptocurrency: Our World's Future Economy? Using this site means that you consent. of their respective owners. We use cookies to ensure you have the best browsing experience on our website. Qt's meta-object system provides the signals and slots mechanism for inter-object communication, run-time type information, and the dynamic property system. P    This generated source file is either #include'd into the class's source file or, more usually, compiled and linked with the class's implementation. U    N    6 Cybersecurity Advancements Happening in the Second Half of 2020, 6 Examples of Big Data Fighting the Pandemic, The Data Science Debate Between R and Python, Online Learning: 5 Helpful Big Data Courses, Behavioral Economics: How Apple Dominates In The Big Data Age, Top 5 Online Data Science Courses from the Biggest Names in Tech, Privacy Issues in the New Big Data Economy, Considering a VPN? Read More. HTML | Viewport meta tag for Responsive Web Design. The Q_OBJECT macro inside the private section of the class declaration is used to enable meta-object features, such as … Terms of Use - code. From the meta-object system's point of view, a QObject subclass without meta code is equivalent to its closest ancestor with meta-object code. How Can Containerization Help with Project Speed and Efficiency? See also QMetaObject, Qt's Property System, and Signals and Slots. Viable Uses for Nanotechnology: The Future Has Arrived, How Blockchain Could Change the Recruiting Game, C Programming Language: Its Important History and Why It Refuses to Go Away, INFOGRAPHIC: The History of Programming Languages, 5 SQL Backup Issues Database Admins Need to Be Aware Of, Online Learning: Top 5 eBooks for Machine Learning Experts. The UML metamodel is defined in MOF. The pointer is then set to 0. Simpler rules for modelling metadata. Meta is a prefix that -- in most information technology usages -- means "an underlying definition or description." their respective owners. Techopedia Terms:    - Renew or change your cookie consent, Optimizing Legacy Enterprise Software Modernization, How Remote Work Impacts DevOps and Development Trends, Machine Learning and the Cloud: A Complementary Partnership, Virtual Training: Paving Advanced Education's Future, IIoT vs IoT: The Bigger Risks of the Industrial Internet of Things, MDM Services: How Your Small Business Can Thrive Without an IT Team. Scheme attribute: This attribute is used to specify a scheme to interpret the property’s value. We bake cookies in your browser for a better experience. Experience. G    For example, let's assume MyWidget inherits from QWidget and is declared with the Q_OBJECT macro: The obj variable, of type QObject *, actually refers to a MyWidget object, so we can cast it appropriately: The cast from QObject to QWidget is successful, because the object is actually a MyWidget, which is a subclass of QWidget. R    Smart Data Management in a Post-Pandemic World. Straight From the Programming Experts: What Functional Programming Language Is Best to Learn Now? Top 10 Projects For Beginners To Practice HTML and CSS Skills. edit How to set the view-port meta tag for iPhone that handles rotation properly ? How to set the default value for an HTML element? It attempts to cast its argument to the pointer type specified in angle-brackets, returning a non-zero pointer if the object is of the correct type (determined at run-time), or 0 if the object's type is incompatible. Q    What resources are available for Sharepoint monitoring, Exchange monitoring and analysis of other Microsoft products? We’re Surrounded By Spying Machines: What Can We Do About It? Metamodels provide a platform-independent mechanism that is used to specify the shared structure, syntax and semantics of technology and tool frameworks, with the ability to share interchangeable formats and programming models for model transformation and querying. Are Insecure Downloads Infiltrating Your Chrome Browser? The qobject_cast() function behaves similarly to the standard C++ dynamic_cast(), with the advantages that it doesn't require RTTI support and it works across dynamic library boundaries. brightness_4 Metamodels provide a platform-independent mechanism that is used to specify the shared structure, syntax and semantics of technology and tool frameworks, with the ability to share interchangeable formats and programming models for model transformation and querying. i.e., it is an OMG-standard metamodelling language. O    You can set object metadata at the time you upload it. How to insert spaces/tabs in text using HTML/CSS? Each Amazon S3 object has data, a key, and metadata. The DOM Meta Object is used to represent the HTML element. Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below. How to calculate the number of days between two dates in javascript? Answers that claim Django model's Meta and metaclasses are "completely different" are misleading answers.. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Are These Autonomous Vehicles Ready for Our World? By using our site, you Please write to us at contribute@geeksforgeeks.org to report any issue with the above content. Tech's On-Going Obsession With Virtual Reality. The meta-object system is based on three things: The QObject class provides a base class for objects that can take advantage of the meta-object system. Therefore, we strongly recommend that all subclasses of QObject use the Q_OBJECT macro regardless of whether or not they actually use signals, slots, and properties. What's the difference between meta name and meta property? Supported Browsers: The browser supported by DOM Meta Object are listed below: If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. A metaclass is used in object oriented programming and is typically thought of as a classes' class. See your article appearing on the GeeksforGeeks main page and help other Geeks. close, link F    Reinforcement Learning Vs. Example-2: Meta Object can be created by using thedocument.createElement Method. Since we know that obj is a MyWidget, we can also cast it to MyWidget *: The cast to MyWidget is successful because qobject_cast() makes no distinction between built-in Qt types and custom types. More of your questions answered by our Experts.

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