Php global space

If no namespace is defined, all classes and functions are defined in the global space, just as before the introduction of the namespace concept in PHP. Prefix \ is added before the name to indicate that the name is in the global space, even if the name is in another namespace. If no namespace is defined, all classes and functions are defined in the global space, just as before the introduction of the namespace concept in PHP. Prefix \ is added before the name to indicate that the name is in the global space, even if the name is in another namespace.

Global Space usage