Re: Destroy a Singleton : static or not static ?
requinham <requinham@gmail.com> wrote in news:9f837bbe-cc20-45d3-adef-
3e7e8dc0df41@u9g2000yqb.googlegroups.com:
On 16 f?v, 14:16, "Leigh Johnston" <le...@i42.co.uk> wrote:
"requinham" <requin...@gmail.com> wrote in message
news:b31460c5-db1e-488f-a1fb-
1cf1ad2f0d7f@b2g2000yqi.googlegroups.com...
Hello,
i would know if the conception of singeleton pattern define the
function who destroy the unique instance as static or not ?
because in the code of global program, this function must be the
latest function executed by the singleton and after that she will
return the handle to the main or another independant function so
it's
not necessary to define this method (destroy()) as static !
Could you be more specific as there are various ways of implementing a
singleton. ?If you are using the Meyers Singleton then there is no
need
for
a destroy function static or otherwise as the singleton is destroyed
automatically at the appropriate time during program termination.
/Leigh
thinks for all for this qwickly response :)
for the implementation, i use a simple and classic method like this :
class A {
private:
A(){};
A(const A& instance){};
~A(){};
static A* uniqueInstance=NULL;
public:
static A* getInstance(){
if (uniqueInstance==NULL)
uniqueInstance=new A();
return uniqueInstance;
}
void destroy(){
if (uniqueInstance != NULL){
delete uniqueInstance;
uniqueInstance=NULL;
}
}
This is fine, except that you should delete and forget the destroy()
function. Your A destructor is empty, so destroying it would not
accomplish anything. And OS will make a better job on releasing the
process memory than you can.
Also, I would return a reference from getInstance(), not a pointer. (I
would still use the static pointer in the implementation, to avoid the
problems with destruction order of statics).
hth
Paavo