Re: What's wrong with this code?

From:

Greg Herlihy <greghe@pacbell.net>

Newsgroups:

comp.lang.c++.moderated

Date:

Thu, 10 May 2007 14:12:31 CST

Message-ID:

<1178776750.103474.255840@u30g2000hsc.googlegroups.com>

On May 9, 8:11 am, loose AT astron DOT nl <l...@astron.nl> wrote:

Could anyone tell me what's wrong with the code below? It segfaults
when the first element is being inserted in the map.

<code>
#include <map>
#include <string>
#include <iostream>

using namespace std;

class Init
{
public:
   Init();
private:
   static map<int, string> map_;
   static Init init_;

};

If there is only one instance of a class then it makes little sense
for that class to have a static member - because all of its members
are effectively static anyway. So in this example, the initialization
order problem is best fixed by declaring Init's "map_" data member as
an ordinary (non-static) data member. Moreover, to prevent other
instances of Init objects (aside from init_) from being created,
Init's constructor should be made private:

     class Init
     {
     private:
         Init();
         map<int, string> map_;
         static Init init_;
     };

     Init Init::init_;

Greg

--
      [ See http://www.gotw.ca/resources/clcm.htm for info about ]
      [ comp.lang.c++.moderated. First time posters: Do this! ]