In this series on learning singleton pattern, we learned lazy initialization and eager initialization with practical examples. We also learned why it is necessary to make the singleton class sealed with the sealed keyword. In this article, I’ll try to explain the differences between static and s...
To overcome this situation, we have to write a double-check locking program as below. Example 3 public class Employee { private static Employee instance = null; private static readonly object instanceLock = new object(); private Employee() { } public static Employee GetInstance { get { if ...
// This program illustrates how to write a singleton class (a class that // can have only one instance) in C++. The trick is to make the default // constructor, copy constructor and assignment operator all private. A // static function GetInstance returns the one and only ...
32 bit app - how to get 'C:\program files" directory using "Environment.GetFolderPath" 32 bit Application calling 32 bit DLL "An attempt was made to load a program with an incorrect format. (Exception from HRESULT: 0x8007000B)" 4 digit precision- String format 405 method not allowed(p...
Supported by National Key Research & Development Program (2016YFC1000204); Science Foundation for Distinguished Young Scholars in Jiangsu (BK20161031); National Natural Science Foundation of China (81602927); Cheung Kong Scholars Programme of China, the QingLan Project of the Jiangsu Province, Jiangsu...
I wrote a little program, LockHeader, that shows how to do it. LockHeader has a menu command View | Lock Columns that's similar to the Lock Toolbars command in Explorer (see Figure 1). When the user invokes View | Lock Columns, LockHeader prevents sizing the column headers...
But the ability to dynamically destroy a Singleton isn't handled by most Singleton implementations. After the Singleton has been manually destroyed, it needs to automatically resurrect itself the next time it's used in the program. Also, if the Singleton exists when the program terminates, it ...
This means they can’t use information known only once the program is up and running (for example, configuration loaded from a file). It also means they can’t reliably depend on each other — the compiler does not guarantee the order in which statics are initialized relative to each...
This will most likely result in a crash on program exit. In his Modern C++ Design book, Alexandrescu presents several solutions to this destruction order problem, including resurrecting the singleton if it is needed after it has been destroyed, increasing the longevity of a singleton so that it...
class SingletonMeta(type): def __init__(cls, *args, **kwargs): super().__init__(*args, **kwargs) cls._instance = None cls._locker = threading.Lock() @property def instance(self, *args, **kwargs): if self._instance is None: with self._locker: if self._instance is None: ...