Re: newbie question on singleton class

From:
=?ISO-8859-1?Q?Erik_Wikstr=F6m?= <Erik-wikstrom@telia.com>
Newsgroups:
comp.lang.c++
Date:
Sat, 12 May 2007 14:39:13 GMT
Message-ID:
<lkk1i.196$Tk3.328@newsb.telia.net>
On 2007-05-12 15:53, pauldepstein@att.net wrote:

I liked this article by Danny Kalev on the singleton design class:
http://gethelp.devx.com/techtips/cpp_pro/10min/10min0200.asp

However I was confused by this:

QUOTE BEGINS HERE
The class's implementation looks like this:

  Singleton* Singleton::pinstance = 0;// initialize pointer
  Singleton* Singleton::Instance ()
  {
    if (pinstance == 0) // is it the first call?
    {
      pinstance = new Singleton; // create sole instance
    }
    return pinstance; // address of sole instance
  }
  Singleton::Singleton()
  {
    //... perform necessary instance initializations
  }

QUOTE ENDS HERE

My confusion stems from the fact that pinstance is a private static
member of Singleton.

So I would have thought that Singleton* Singleton::pinstance = 0;
violates private access.

What am I missing?


That's the only way to initialize a static member, since they have to be
initialized before the rest of the program is run.

--
Erik Wikstr?m

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