Obtains a symbol from the global registry. If no symbol exists for the key within the registry a new symbol is
created and stored in the global registry.
From version 21.2.
The key for a symbol within the global registry.
The found or newly created symbol.
Returns the key within the global symbol registry under which the given symbol is stored.
The symbol to look for.
The key for the given symbol if the symbol is known to the global registry, else return