In computer programming

Computer programming

Computer programming is the process of designing, writing, testing, debugging, and maintaining the source code of computer programs. This source code is written in one or more programming languages. The purpose of programming is to create a program that performs specific operations or exhibits a...

 a singleton variable is a variable

Variable (programming)

In computer programming, a variable is a symbolic name given to some known or unknown quantity or information, for the purpose of allowing the name to be used independently of the information it represents...

 that is referred to only once.

Examples of where a variable might only be referenced once is as a dummy argument in a function call, or when its address is assigned to another variable which subsequently accesses its allocated storage.

Singleton variables sometimes occur because a mistake has been made – such as assigning a value to a variable and forgetting to use it later, or mistyping one instance of the variable name. Some compiler

Compiler

A compiler is a computer program that transforms source code written in a programming language into another computer language...

s and lint

Lint programming tool

In computer programming, lint was the name originally given to a particular program that flagged some suspicious and non-portable constructs in C language source code. The term is now applied generically to tools that flag suspicious usage in software written in any computer language...

-like tools flag occurrences of singleton variables.