It is possible that this method signature was created as a by-product of some generic class. For example, SwingWorker has two type parameters, one for final result and one for intermediate results. If you just don’t want to use any intermediate results, you pass Void as the type parameter, resulting in some methods returning Void … Read more
You should avoid async void. Only use async void for event handlers. DelegateCommand is (logically) an event handler, so you can do it like this: // Use [InternalsVisibleTo] to share internal methods with the unit test project. internal async Task DoLookupCommandImpl(long idToLookUp) { IOrder order = await orderService.LookUpIdAsync(idToLookUp); // Close the search IsSearchShowing = false; … Read more
Yes, you can return from a void function. Interestingly, you can also return void from a void function. For example: void foo() { return void(); } As expected, this is the same as a plain return;. It may seem esoteric, but the reason is for template consistency: template<class T> T default_value() { return T(); } … Read more
const void is a type which you can form a pointer to. It’s similar to a normal void pointer, but conversions work differently. For example, a const int* cannot be implicitly converted to a void*, but it can be implicitly converted to a const void*. Likewise, if you have a const void* you cannot static_cast … Read more
Best practice is to mark function async void only if it is fire and forget method, if you want to await on, you should mark it as async Task. In case if you still want to await, then wrap it like so await Task.Run(() => blah())
Because it’s simply the way the language is defined. A method can use return statements to return control to its caller. In a method returning void, return statements cannot specify an expression. In a method returning non-void, return statements must include an expression that computes the return value. It’s an arbitrary decision (presumably made for … Read more
The overwhelming majority of the time, one of int main(void) or int main(int argc, char* argv[]) is what you need to use. In particular, if you’re writing a program that’s going to be compiled by any major compiler for running on a personal computer, with the full set of the C standard libraries, then you … Read more
From the documentation: The Void structure is used in the System.Reflection namespace, but is rarely useful in a typical application. The Void structure has no members other than the ones all types inherit from the Object class. There’s no reason really to use it in code. Also: var nothing = new void(); This doesn’t compile … Read more
This as written is legal. The cast back to MyCls* is critical. Without that, you will invoke undefined behavior–the MyCls destructor will not be called, and other problems may arise as well (such as a crash). You must cast back to the correct type. Also note that this can be complicated if multiple inheritance is … Read more
You cannot declare a variable of type void because variables must have object type or be references, extern void f; doesn’t declare a reference, and void is not an object type: Section 3 [basic] says that A variable is introduced by the declaration of a reference other than a non-static data member or of an … Read more