Re: linker error in singleton implementation

From:

=?ISO-8859-1?Q?Erik_Wikstr=F6m?= <Erik-wikstrom@telia.com>

Newsgroups:

comp.lang.c++

Date:

Sat, 14 Jul 2007 16:58:32 GMT

Message-ID:

<Yg7mi.4127$ZA.1776@newsb.telia.net>

On 2007-07-14 17:22, sam_cit@yahoo.co.in wrote:

On Jul 14, 8:14 pm, Erik Wikstr?m <Erik-wikst...@telia.com> wrote:

On 2007-07-14 16:43, sam_...@yahoo.co.in wrote:

Hi everyone,

I have the following code and it gives a linker error on MS vc++ 6.0.

error LNK2001: unresolved external symbol "protected: __thiscall
Singleton::Singleton(void)" (??0Singleton@@IAE@XZ)

#include <stdlib.h>

class Singleton
  {
  public:
      static Singleton* Instance();
  protected:
     Singleton();
      Singleton(const Singleton&);
      Singleton& operator= (const Singleton&);
  private:
      static Singleton* pinstance;
  };

Singleton* Singleton::pinstance = 0;

Singleton* Singleton::Instance()
{
   pinstance = new Singleton();
   return pinstance;
}

int main()
{
   Singleton::Instance();
   return(0);
}

Can anyone help in this regard?

Implement the constructor.

--
Erik Wikstr?m- Hide quoted text -

- Show quoted text -

Thanks everyone, and by the way i was just thinking of moving the
cons, copy cons and operator function to private section, wouldn't
that also server the purpose of singleton implementation?

Currently there's no real difference between having them protected and
private, you'd still have to implement the constructor. The only
difference would be if you inherit from Singleton, unless you plan to do
that you can have the private.

--
Erik Wikstr?m