Singleton: Difference between revisions

This version doesn't require [[Mutex#C|Mutex]], but it is not safe in a multi-threaded environment (before C++11).

// And any other protected methods.

}</lang>

=== Thread safe (since C++11) ===

This will be thread safe since C++11, where static variables is always thread-safe (according to section 6.7 of The Standard).

<lang cpp>class Singleton

{

public:

static Singleton & Instance()

{

// Since it's a static variable, if the class has already been created,

// It won't be created again.

// And it **is** thread-safe in C++11.

static Singleton myInstance;

// Return a reference to our instance.

return myInstance;

}

// delete copy and move constructors and assign operators

Singleton(Singleton const&) = delete; // Copy construct

Singleton(Singleton&&) = delete; // Move construct

Singleton& operator=(Singleton const&) = delete; // Copy assign

Singleton& operator=(Singleton &&) = delete; // Move assign

// Any other public methods

protected:

Singleton()

{

// Constructor code goes here.

}

~Singleton()

{

// Destructor code goes here.

}