Re: singleton

Ian Collins <>
Tue, 25 Mar 2008 22:03:37 +1300
[please don't top-post, corrected]

Colin wrote:

On Mar 25, 10:17 am, thomas <> wrote:

hi guys,
class A{
    static A *getInstance(){
       static A *a = new A(); //-------L1----
       return a;


I use the static keyword to declare a static instance A,
I wonder if getInstance() is called multiple times, will L1 be
executed multiple times?

generally a initialization sentence of static variable will be
executed only once, but I'm not sure what will the c++ compiler expand
for L1.

class A{
    static A* a=null;

The above is illegal (you can't initialise a non-const static member
this way) and you haven't declared null.

    static A *getInstance(){
          a=new A(); //remeber delete it..

This form is only really useful if you intend to delete the singleton.

Ian Collins.

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