singleton_base

Header: singleton_base.h

Allows creation of a singleton base class.

The class to apply to needs to derive from it. I.e. singleton_base is intrusive.

etl::singleton_base<typename T>

T The type to use as a singleton.

The class derived from this must call the constructor with the instance of itself. Multiple calls to the constructor will result in an etl::singleton_base_already_created assertion.

Before the constructor Is called, the singleton is in the invalid state.

Static functions

static T& instance()

Returns a reference to the one instance of T.
Asserts an etl::singleton_base_not_created if the instance has not been attached.

static bool is_valid()

Returns true if the instance is has been attached, otherwise false.

Example

class MyType : public etl::singleton_base<MyType>
{
public:
  MyType()
    : etl::singleton_base<MyType>(*this)
  {
  }
};

MyType my_instance;              // Construct the singleton instance.

bool is_valid;
is_valid = MyType::is_valid();   // true

MyType& mt = MyType::instance(); // Get the instance

singleton successor