165:(which is sometimes confusingly called the "void type"). Unlike a real unit type which is a singleton, the void type lacks a way to represent its value and the language does not provide any way to declare an object or represent a value with type
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had the feature, now seen as an annoyance, of generating a warning on any function call that did not use the function's returned value. Old code sometimes
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began his work on C++ in 1979–1980, void and void pointers were part of the C language dialect supported by AT&T-derived compilers.
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and functions with no arguments simply had empty argument lists. Pointers to untyped data were declared as integers or pointers to
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functions. The C language standard does not guarantee that the different pointer types have the same size or alignment.
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This article is about the void type in computer programming languages. For the concept of a void pointer, see
327:. Association for Computing Machinery, Inc. via the author and Lucent Technologies Inc. 1996. Archived from
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295:. A function into the void type does not return results, and a side-effectful program with type signature
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normally, but does not provide a result value to its caller. Usually such functions are called for their
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The C syntax to declare a (non-variadic) function with an as-yet-unspecified number of parameters, e.g.
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A function with void result type ends either by reaching the end of the function or by executing a
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267:(and C++), a function prototype with empty parentheses declares a function with zero parameters.
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to indicate that the function takes no arguments. Note that in all of these situations, void is
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In the earliest versions of C, functions with no specific result defaulted to a return type of
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a type qualifier on any value. Despite the name, this is semantically similar to an implicit
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1004:
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390:"WG14-N2432 : Remove support for function definitions with identifier lists proposal"
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C and C++: Case
Studies in Compatibility. Reconcilable differences? You decide
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has different semantics in C and C++, as detailed in the following table:
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such function calls to void to suppress this warning. By the time
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125:. A program can convert a pointer to any type of data (except a
109:), but this is an unrelated notion. Variables of this type are
16:
Return type for functions that do not output values when called
418:"WG14-N2841 : No function declarators without prototypes"
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does not terminate, or crashes. In particular, there are no
486:
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with no returned value. The void type may also replace the
481:
260:
195:
The explicit use of void vs. giving no arguments in a
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template <typename... Ts> void f(Ts... ts) {}
239:accepts a constant but unknown number of arguments
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21:Pointer (computer programming) § C and C++
344:Programming: Principles and Practice Using C++
117:type, so in this context (but not the others)
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428:from the original on November 12, 2022.
406:from the original on December 27, 2022.
346:. Boston: Addison-Wesley. p. 996.
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23:. For types of astronomical voids, see
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74:and syntactic constructs which define
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92:Unit type#In programming languages
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323:The Development of the C Language
121:acts roughly like a universal or
88:functional programming languages
283:functional programming language
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281:Quite contrary to C++, in the
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523:Arbitrary-precision or bignum
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40:several programming languages
82:. It is also similar to the
7:
342:Stroustrup, Bjarne (2009).
319:Ritchie, Dennis M. (1993).
292:, which has no inhabitants
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288:the void type denotes the
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248:(not strictly equivalent)
18:
897:
864:Strongly typed identifier
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515:
472:
259:above, was deprecated in
939:Parametric polymorphism
399:. September 25, 2019.
376:, September 01, 2002;
90:and type theory. See
27:. For other uses, see
29:Void (disambiguation)
303:into the void type.
103:pointer to void type
944:Primitive data type
849:Recursive data type
702:Algebraic data type
578:Quadruple precision
366:Bjarne Stroustrup,
907:Abstract data type
588:Extended precision
547:Reduced precision
197:function prototype
151:function prototype
94:for a comparison.
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719:Associative array
583:Octuple precision
353:978-0-321-54372-1
253:
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190:Bjarne Stroustrup
101:also support the
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959:Type constructor
844:Opaque data type
776:Record or Struct
573:Double precision
568:Single precision
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25:Void (astronomy)
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180:. Some early C
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424:. 2021-10-10.
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1005:Type theory
974:Type theory
969:Type system
819:Bottom type
766:Option type
707:generalized
593:Long double
538:Fixed point
163:bottom type
131:polymorphic
115:unspecified
76:subroutines
52:return type
1000:Data types
994:Categories
879:Empty type
874:Type class
824:Collection
781:Refinement
759:metaobject
607:signedness
466:Data types
374:Dr. Dobb's
307:References
290:empty type
277:Empty type
271:In Haskell
68:procedures
954:Subtyping
949:Interface
932:metaclass
884:Unit type
854:Semaphore
834:Exception
739:Inductive
729:Dependent
694:Composite
672:Character
654:Reference
551:Minifloat
507:Bit array
235:void f();
223:preferred
219:void f();
182:compilers
159:unit type
84:unit type
50:, is the
36:void type
979:Variable
869:Top type
734:Equality
642:physical
619:Rational
614:Interval
561:bfloat16
426:Archived
401:Archived
257:void f()
123:top type
111:pointers
86:used in
56:function
922:Generic
898:Related
814:Boolean
771:Product
647:virtual
637:Address
629:Pointer
602:Integer
533:Decimal
528:Complex
516:Numeric
297:IO Void
286:Haskell
60:returns
48:Algol68
912:Boxing
900:topics
859:Stream
796:tagged
754:Object
677:String
350:
119:void *
107:void *
97:C and
72:Pascal
807:Other
791:Union
724:Class
714:Array
497:Tryte
404:(PDF)
393:(PDF)
263:. In
186:casts
149:of a
58:that
54:of a
38:, in
927:Kind
889:Void
749:List
664:Text
502:Word
492:Trit
487:Byte
348:ISBN
178:char
167:void
46:and
34:The
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482:Bit
265:C23
261:C99
174:int
155:not
99:C++
78:in
70:in
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420:.
395:.
372:,
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205:C
169:.
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451:t
444:v
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237:(
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44:C
31:.
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