In computer programming, null is a special value for a pointer (or other kind of reference) used to signify that the pointer intentionally does not have a target. Such pointer with null as its value is called a null pointer. Often, for example in many implementations of the C language, a binary 0 (zero) is used as the null value, as most operating systems consider it an error to try to access such a low memory address. However, null is used in many other computing disciplines (often interchangeably with nul or nil): Wikibooks has more about this subject: Computer programming Computer programming (often simply programming) is the craft of implementing one or more interrelated abstract algorithms using a particular programming language to produce a concrete computer program. ... In computer science, a pointer is a programming language datatype whose value refers directly to (points to) another value stored elsewhere in the computer memory using its address. ... This article discusses a general notion of reference in computing. ... In the C Programming Language, a null pointer is a special pointer which is guaranteed to compare unequal to a pointer to any object or function. ... In computing, an operating system (OS) is the system software responsible for the direct control and management of hardware and basic system operations. ... In colloquial language, nil as an abbreviation of the Latin word nihil (nothing) is sometimes used to express disagreement. ...

In UNIX systems, /dev/null — also referred to as the black hole or bit bucket — is a special file that delivers no input and does nothing with output into it. The NUL device has similar functionality in DOS and Windows. It has been suggested that List of Unixes be merged into this article or section. ... In Unix-like operating systems, /dev/null or the null device is a special file that discards all data written to it, and provides no data to any process that reads from it. ... The bit bucket was the container on Teletype machines or IBM key punch machines into which chad from the paper tape punch or card punch was deposited. ... A device file or special file is an interface for a device driver that appears in a file system as if it were an ordinary file. ...

In the C0 control code set defined in ISO-646 and used in ASCII and Unicode, the code value 0 is the null character. The C0 and C1 control code sets define control codes for use in text. ... There are 95 printable ASCII characters, numbered 32 to 126. ... Unicode is an international standard whose goal is to provide the means by which text of all forms and languages can be encoded for use by computers. ... The null character (also null terminator) is a character with the value zero, present in the ASCII and Unicode character sets, and available in nearly all mainstream programming languages. ...

In some programming languages, such as LISP, Pascal (Delphi and pascal variants that are based on it use null for the null variant which leads to somewhat confusing errors if null is accidentally used instead of nil), and Ruby, the designation is called nil. Lisp is a reflective, multi-paradigm programming language with a long history. ... Pascal is an imperative computer programming language, developed in 1970 by Niklaus Wirth as a language particularly suitable for structured programming. ... The theatre, seen from above Delphikjl;lk;kl; (Greek Δελφοί - Delphoi; see also List of traditional Greek place names) is an archaeological site and a modern town in Greece. ... Ruby is a reflective, object-oriented programming language. ... In colloquial language, nil as an abbreviation of the Latin word nihil (nothing) is sometimes used to express disagreement. ...

In many disciplines, the concept of null allows a three-valued logic, with null indicating 'undefined'. For example, this is how NULL is used in the SQL database query language. KK Null, a Japanese musician Null, a special value in computer programming. ... Multi-valued logics are logical calculi in which there are more than two possible truth values. ... Columns in Relational database management systems (RDBMS) can optionally store NULL values. ... SQL(Structured Query Language) is the most popular computer language used to create, modify and retrieve data from relational database management systems. ...

Note that this is not the same as the definition of nothing because it is more related to computer science. Nothing is the lack or absence of anything. ...

See also: Null (SQL) Columns in Relational database management systems (RDBMS) can optionally store NULL values. ...