Return the value of the constant indicated by name. 2) lvalue of any type T may be converted to a lvalue or rvalue reference to the same type T, more or less cv-qualified.Likewise, an prvalue of class type or an xvalue of any type may be converted to a more or less cv-qualified rvalue reference. I.e.
This function works also with class constants. 06/08/2017; 2 minutes to read +1; In this article.

If you want to see if a variable exists, use isset() as defined() only applies to constants.If you … If the constant FOO has not already been defined then it will actually define a constant with the name FOO anyway; this is undesirable behaviour and may have unexpected consequences depending if the constant had already been defined or not, so make sure you always use either single quotes or double quotes when defining the name of the constant. Checks whether the given constant exists and is defined. Note: . The result of a reference const_cast refers to the original object if expression is a glvalue and to the materialized temporary otherwise (since C++17).

'Uncaught ReferenceError: regeneratorRuntime is not defined' makes added external packages and importing fonts in css not working in dockerized production build of … A not defined is a variable which is not declared at a given point of time with declaration keyword like var, let or const. it is stored in a variable or returned by a function. Variable not defined.
Write a declaration that includes an access specifier, the Const keyword, and an expression, as in the following examples:. constant() is useful if you need to retrieve the value of a constant, but do not know its name.

Warning: 08/09 is not a legal ECMA-262 octal constant Warning: Date.prototype.toLocaleFormat is deprecated [Translate] Warning: JavaScript 1.6's for-each-in loops are deprecated [Translate] To declare a constant.