![]() ![]() The actual implementation in a given environment depends on the programming language and target environment, and might differ from the implementation shown here. Note: We will have a look at a typical implementation of null. Run-time Implementationīefore discussing the meaning of null, we need to understand how null is implemented in memory at run-time. But it’s not difficult to translate them into your favorite language. However, this article contains some simple source code examples shown in Java. ![]() Please consult your programming language manuals for specific advice on null. ![]() Explanations are general and not tied to a specific language. Note: This article is programming-language-neutral - as far as possible. After reading this article, everybody should be able to answer such questions without hesitation. What does this mean? Does it mean that Alice doesn't have an email address? Or that her email address is unknown? Or that it is secret? Or does it simply mean that email_address is 'undefined' or 'uninitialized'? Let's see. Here is a simple example: Suppose that Alice’s email_address points to null. Because they think of it as the 'million-dollar mistake', a term coined by Tony Hoare, the inventor of null. Some programmers even try to completely avoid null. We have to understand its semantics and implementation, and we need to know how to use null in our source code.Ĭomments in programmer forums sometimes reveal a bit of confusion with null. So it is essential to fully grasp the idea of null. It is ubiquitous in all kinds of source code written in these languages. Null is a fundamental concept in many programming languages. What is the meaning of null? How is null implemented? When should you use null in your source code, and when should you not use it? Introduction By Christian Neumanns A quick and thorough guide to ‘ null’: what it is, and how you should use it ![]()
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