The first question is why you need to serialize the static members? Static members are associated with the class, not the instances, so it does not make sense to include them when serializing an instance. The first solution is to make those members not static. Or, if those members are the same in the original … Read more
Consider: template<typename T, T> struct value { }; template<typename T> struct HasStatics { static int a; // we force this to be initialized typedef value<int&, a> value_user; }; template<typename T> int HasStatics<T>::a = /* whatever side-effect you want */ 0; It’s also possible without introducing any member: template<typename T, T> struct var { enum { … Read more
While the exact details of the type system are implementation dependent, let me go into some more detail than just stating that it depends and you should not care. I’ll describe how it approximately works in Microsoft’s implementation (.NET) according to the book CLR via C# by Jeffrey Richter and the article See How the … Read more
TL;DR: Your example is well-defined. Merely dereferencing a null pointer is not invoking UB. There is a lot of debate over this topic, which basically boils down to whether indirection through a null pointer is itself UB. The only questionable thing that happens in your example is the evaluation of the object expression. In particular, … Read more
This was discussed on usenet some time ago, while i was trying to answer another question on stackoverflow: Point of Instantiation of Static Data Members. I think it’s worth reducing the test-case, and considering each scenario in isolation, so let’s look at it more general first: struct C { C(int n) { printf(“%d\n”, n); } … Read more
No, static members are associated with the Type, which is associated with the AppDomain it’s loaded in. Note that there doesn’t have to be any instances of HasStatic for the class to be initialized and the shared variable to have a reference to a List<string>. Unless you’re considering situations where AppDomains get unloaded, static variables … Read more
Your methods are missing the static keyword. Change function getInstanceByName($name=””){ to public static function getInstanceByName($name=””){ if you want to call them statically. Note that static methods (and Singletons) are death to testability. Also note that you are doing way too much work in the constructor, especially all that querying shouldn’t be in there. All your … Read more
PHP can’t parse non-trivial expressions in initializers. I prefer to work around this by adding code right after definition of the class: class Foo { static $bar; } Foo::$bar = array(…); or class Foo { private static $bar; static function init() { self::$bar = array(…); } } Foo::init(); PHP 5.6 can handle some expressions now. … Read more
Lets start with a bit of background: What happens when you start an application? The OS starts a process and assigns it a unique process id and allocates a process table.A process start an instance of DVM(Dalvik VM); Each application runs inside a DVM. A DVM manages class loading unloading, instance lifecycle, GC etc. Lifetime … Read more
what I want to know is why java forbids static fields/methods inside inner classes Because those inner classes are “instance” inner classes. That is, they are like an instance attribute of the enclosing object. Since they’re “instance” classes, it doesn’t make any sense to allow static features, for static is meant to work without an … Read more