void

I read this MSDN article: Unit Type (F#) ...The unit type is a type that indicates the absence of a specific value; the unit type has only a single value, which acts as a placeholder when no other value exists or is needed ... The unit type resembles the void type in languages such as C# and C++... So... Alright, I understand, that the unit type is such a type, which has only a single value () . But I have some questions: Why is it needed? When is it needed? I don't understand why not to use the void type in F#, like C# and C++ use. If I look at the following table: Primitive Types (F#) Type

void is a bizarre wart in the C++ type system. It's an incomplete type that cannot be completed, and it has all sort of magic rules about the restricted ways it can be employed: A type cv void is an incomplete type that cannot be completed; such a type has an empty set of values. It is used as the return type for functions that do not return a value. Any expression can be explicitly converted to type cv void ([expr.cast]). An expression of type cv void shall be used only as an expression statement, as an operand of a comma expression, as a second or third operand of ?: ([expr.cond]), as the

I have some "confusion" about void and return. In general, I understand void is used in methods without returning anything, and return is used in methods when I want to return something to the calling code. But in the following code, I can use both, and my question is, which one to use? And how to determine? Is it about performance? Normally, I have the same results in both cases. public class Calc { private double number; Calc (double n) { number = n; } public void add(double n) { number += n; } public double add1(double n) { return number = number + n; } } Thank you! This method : public

In my project I have a Settings form and a Main form. I'm trying to call the Main form's MasterReset function from the Setting form, but nothing happens. The Master form's Masterreset function looks like this. public void MasterReset() { DialogResult dialogResult = MessageBox.Show("Are you sure you want to perform master reset? All settings will be set to default.", "Warning", MessageBoxButtons.YesNo, MessageBoxIcon.Warning); if (dialogResult == DialogResult.Yes) { string path = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData); string phonebook_path = path + "\\Phonebook\

Apparently, it is possible to declare a function returning const void : const void foo() { } g++ seems to consider the const important, because the following code does not compile: #include <type_traits> static_assert(std::is_same<void(), const void()>::value, "const matters"); So does const void have any practical significance? Not really. But to ignore cv -qualifications on void or to make them errors could create unnecessary complexity in terms of both compiler implementation and end-user code. Consider templates like template<typename T> const T ... There's no reason to make using void in

gcc-4.8 accepts this code, but isn't it wrong since the non-type parameter pack is equivalent to void... which is illegal? template <typename T, typename std::enable_if<std::is_integral<T>::value>::type...> void test(T) {} I tried this with clang-3.5 as well which also accepts it. Is this a compiler bug, or am I misunderstanding something? Full test code below, which uses non-type empty parameter packs to simplify enable_if. This is almost the same as what's in Flaming Dangerzone's Remastered enable_if except after substitution the pack becomes void... . #include <type_traits> template <

I was given a piece of code that uses void() as an argument. The code doesn't compile... obviously? Can we instantiate anything of type void ? I believed the answer was no, with the exception of a void* . For example: Writing the function void askVoid(void param) {} errors: A parameter may not have void type Writing the function void askNaught() {} and calling it with askNaught(void())` errors: error C2660: takeNaught : function does not take 1 arguments Writing the templatized function template <typename T> void takeGeneric(T param) {} and calling it with takeGeneric(void()) errors: error