Unreferenced variable: Difference between revisions

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{{Short description|Variable which is defined but never used}}

{{Unreferenced|date=February 2007}}

An '''unreferenced variable''' in the [[source code]] of a [[computer program]] is a [[Variable (programming)|variable]] that is defined but which is never used. This may result in a harmless waste of memory. (unless theMany [[compiler]]s useddetect detectssuch the situationvariables and doesdo not allocate storage for thethem variable(i.e., "optimize away" their storage), perhapsgenerally also issuing a warning) as they do.<ref>{{Cite book Some|last1=Blair-Chappell [[coding|first1=Stephen style|codingurl=https://books.google.com/books?id=n3DtR4mQNmwC guideline]]|title=Parallel documentsProgramming considerwith anIntel unreferencedParallel variableStudio toXE be|last2=Stokes a|first2=Andrew symptom|date=2012-04-19 of|publisher=John aWiley potential& codingSons fault.|isbn=978-1-118-23488-4 |pages=108 |language=en}}</ref>

Some [[coding style|coding guideline]] documents consider an unreferenced variable to be a symptom of a potential coding fault. On the other hand, unreferenced variables can be used as temporary placeholders to indicate further expected future developments in the code.

==Examples==

[[C (programming language)|C]]:

<sourcesyntaxhighlight lang="c">

int main(void)

{

Line 12 ⟶ 14:

return 0;

}

</syntaxhighlight>

</source>

In this example, '''j''' is an unreferenced variable.

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