The void type, in several programming languages derived from C, is the type for the result of a function that produces no direct result. Usually such functions are called for their side effects, much like subroutines in Visual Basic and procedures in Pascal. A function with void result type ends either by reaching the end of the function or by executing a return statement with no returned value. In C, the void type also appears in the argument lists of function prototypes to indicate that the function takes no arguments. In all of these situations, the void type serves as a unit type. The language does not allow the use of the void type in variable declarations. Curly brace or bracket programming languages are those which use balanced brackets ({ and }, also known as brace brackets or simply braces) in their syntax or formal grammar, mainly due to being C-influenced. ... At the broadest level, type theory is the branch of mathematics and logic that concerns itself with classifying entities into collections called types. ... In computer science, a subroutine (function, procedure, or subprogram) is a sequence of code which performs a specific task, as part of a larger program, and is grouped as one, or more, statement blocks; such code is sometimes collected into software libraries. ... Side-effect can mean: Side-effect (computer science), a state change caused by a function call Adverse drug reaction, an unintended consequence specifically arising from drug therapy Therapeutic effect (medicine), a desirable consequence of any kind of medical treatment, even though resulting as an unintended, unexpected consequence of the treatment... The four colored boxes is the logo of VBA, and the two drums above them symbolize database connectivity Visual Basic (VB) is an event driven programming language and associated development environment prototyped by Alan Cooper as Project Ruby, then bought and vastly improved upon by Microsoft. ... Pascal is an imperative computer programming language, developed in 1970 by Niklaus Wirth as a language particularly suitable for structured programming. ... In computer programming, subprograms (functions) will return to the higher-level programs, which called them; return ends the current task. ... Function arguments are values or references to language constructs (like variables) which are passed to a function. ... A function prototype in C or C++ is a declaration of a function that omits the function body but does specify the functions name, arity, argument types and return type. ... A unit type is a mathematical type that allows only one value. ... In computer science and mathematics, a variable is a symbol denoting a quantity or symbolic representation. ...

C and C++ also support the type pointer to void (specified as "void *"), which despite the name has little to do with the other uses of void. Variables of this type are pointers to data of an unspecified type, so in this context (but not the others) void acts as a universal or top type. A program can convert a pointer to any type of data to a pointer to void and back to the original type without losing information, which makes these pointers useful for polymorphic functions. C++ (generally pronounced see plus plus) is a general-purpose programming language. ... It has been suggested that Software pointer be merged into this article or section. ... In computer science, polymorphism means allowing a single definition to be used with different types of data (specifically, different classes of objects). ...

The void type is a product of Standard C. In earlier versions of C, functions with no specific result defaulted to a return type of "int" and functions with no arguments simply had empty argument lists. Pointers to untyped data were declared as integers or pointers to "char". Some early C compilers 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 casts such function calls to void to suppress this warning. ANSI C (Standard C) is a variant of the C programming language. ... A diagram of the operation of a typical multi-language compiler. ... This article should be merged with type_conversion. ...