Static Initialization of Base Class' member

[danil52@mail.ru]

Hello there.
I have an abstract Base class with bunch of private static members and
public static getters for those members.

I want my Derived classes to call a static constructor and initialize
those members. How can this be achieved? Thank you.

[mlimber]

Re: Static Initialization of Base Class' member

On Jul 25, 1:31 pm, dani...@mail.ru wrote:

Hello there.
I have an abstract Base class with bunch of private static members and
public static getters for those members.
>
I want my Derived classes to call a static constructor and initialize
those members. How can this be achieved? Thank you.

Use a protected static initializer function:

class Base
{
static int i;
protected:
static void Init( const int j ) { i = j; }
public:
static int GetI() { return i; }
};

int Base::i = 0;

class Derived : public Base
{
public:
Derived() { Init( 42 ); }
};

Cheers! --M

[danil52@mail.ru]

Re: Static Initialization of Base Class' member

On Jul 25, 1:39 pm, mlimber <mlim...@gmail. comwrote:

On Jul 25, 1:31 pm, dani...@mail.ru wrote:
>

Hello there.
I have an abstract Base class with bunch of private static members and
public static getters for those members.

>

I want my Derived classes to call a static constructor and initialize
those members. How can this be achieved? Thank you.

>
Use a protected static initializer function:
>
 class Base
 {
   static int i;
 protected:
   static void Init( const int j ) { i = j; }
 public:
   static int GetI() { return i; }
 };
>
 int Base::i = 0;
>
 class Derived : public Base
 {
 public:
   Derived() { Init( 42 ); }
 };
>
Cheers! --M

Thank you for your quick response. The version that you gave me does
work, however, as you can see, the static Init() gets called every
time a new instance is being created. To me, it defeats the whole
purpose of the object being static in the first place. Is there a way
for me to call the static Init() only once? I tried to put
"Derived::Init( )" but that didn't compile.

[=?ISO-8859-1?Q?Dar=EDo_Griffo?=]

Re: Static Initialization of Base Class' member

On Jul 25, 2:57 pm, dani...@mail.ru wrote:

On Jul 25, 1:39 pm, mlimber <mlim...@gmail. comwrote:
>
>
>

On Jul 25, 1:31 pm, dani...@mail.ru wrote:

>

Hello there.
I have an abstract Base class with bunch of private static members and
public static getters for those members.

>

I want my Derived classes to call a static constructor and initialize
those members. How can this be achieved? Thank you.

>

Use a protected static initializer function:

>

 class Base
 {
   static int i;
 protected:
   static void Init( const int j ) { i = j; }
 public:
   static int GetI() { return i; }
 };

>

 int Base::i = 0;

>

 class Derived : public Base
 {
 public:
   Derived() { Init( 42 ); }
 };

>

Cheers! --M

>
Thank you for your quick response. The version that you gave me does
work, however, as you can see, the static Init() gets called every
time a new instance is being created. To me, it defeats the whole
purpose of the object being static in the first place. Is there a way
for me to call the static Init() only once? I tried to put
"Derived::Init( )" but that didn't compile.

Base::Init
{
static bool first = true;
if(first)
{
first = false;
//do your stuff WARNING NOT THREAD SAFE
}
}

this Init is called only once

[Joe Greer]

Re: Static Initialization of Base Class' member

danil52@mail.ru wrote in news:dae40744-516d-4e3f-b166-
de7a737f89ef@x2 9g2000prd.googl egroups.com:

>
Thank you for your quick response. The version that you gave me does
work, however, as you can see, the static Init() gets called every
time a new instance is being created. To me, it defeats the whole
purpose of the object being static in the first place. Is there a way
for me to call the static Init() only once? I tried to put
"Derived::Init( )" but that didn't compile.
>

If you require dynamic initialization, you can't help it being called, but
you can protect it with a boolean that gets set to true after the init()
call finishes. Like so:

class Whatever {
static bool initialized;
static void Init()
{
if (!initialized)
{
// init stuff
initialized = true;
}
}

};

bool Whatever::initi alized = false;


You might also consider a singleton instead of statics.

joe