How to create singleton class inline

i have a working example for a singleton class

file exmpl.hpp

Code:

---

class cX
{
  private:
  static cX *iX;
  public:
  static cX* Create()
  {
    if(iX==NULL)
    {
      iX=new cX();
    }
    return iX;
  };
};

---

and
file: exmpl.cpp

Code:

---

cX* cX::iX=NULL;  // INIT <- THIS

---

somebody an idea how to put that together into 1 header?

You cannot put the contents of exmpl.cpp in the header because it contains a variable definition (that of the static member pointer). If the header were included in more than one source file, the variable would be defined more than once, which is an error.

By the way, it is more conventional to name Create as Get since the object is only created once, and transparently to the caller.

i'm using #ifndef __c_X__ #define __c_X__ ... class code etc ... #endif in each header that should avoid that redeclaration or not? just a q cause i didnt mentioned that before but i think u know what ure talking about ;-)

ure right - when i try to set the iX outside the class at the top compiler is missing constructor and destructor and below compiler says multiple definition

i asked for a solution i probably didnt think about

thanks again ;-)

Quote:

---

Originally Posted by NA9x2000

i'm using #ifndef __c_X__ #define __c_X__ #endif in each header that should avoid that redeclaration or not?

---

No, it won't. It would only help avoid the problem when the header is included multiple times in the same source file.

By the way, names that begin with an underscore followed by an uppercase letter, or that contain consecutive underscores, are reserved to the (compiler and standard library) implementation for any use. As such, your proposed __c_C__ identifier is reserved and hence you should not be defining it.

O_o

If you want to convince me that you need a singleton (versus simply declaring a global instance of a class), I'll happily tell you how to do it "inline".

Soma

oh buddy what are u waiting for?? xD tell me plz :D

i'll remove that underscores thx LL