initialization of static data member in header file

Hi there

I am trying to provide a lookup from two 'int's into a char array,
something like this:

template <int g, int estruct Lookup;
template <struct Lookup<0,0{
// some typedef + enums definitions
static const char A;
};
const char Lookup<0,0>::A = "BLA";
// continue with Lookup<0,1; Lookup<0,2...

Since the initialization is done in the .h file, it gets included
multiple times, and at link time I am getting duplicate symbols.

Is there another way to initialize static data members ? Or could
someone let me know of any work around ?

Thanks for suggestion,
-Mathieu
Ps: Full source code is here:
http://gdcm.svn.sourceforge.net/view....h?view=markup

re: initialization of static data member in header file

mathieu wrote:You're trying to initialise an object of type 'char' with a character
array. That's impossible. A char array is not convertible to 'char'.
Another? Not sure what you mean. Whatever you posted is _not_
a way to initialise it.
Define and initialise static data in a separate translation unit.
It's not a work-around. It's the only way to do it.
V
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re: initialization of static data member in header file

On Feb 11, 3:29 pm, "Victor Bazarov" <v.Abaza...@comAcast.netwrote:Sorry I meant:

....
static const char A[];
....
const char Lookup<0,0>::A[] = "BLA";

Ok. This might be naive, but I was able to do it with typdef and enum,
I tought I could do the same with a char array...
After all I might have to require user of my lib to link to it,
instead of just including it.

-Mathieu

re: initialization of static data member in header file

mathieu wrote:Not sure what you mean here. Any code sample?
Static data are special beasts. You can definitely forgo linking if
all you have is code and it's all in templates.

V
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re: initialization of static data member in header file

On Feb 11, 4:08 pm, "Victor Bazarov" <v.Abaza...@comAcast.netwrote:Thanks Victor for taking the time to try to help me out :)
The code is exactly:

http://gdcm.svn.sourceforge.net/view....h?view=markup

Again I'll use the notion of lookup. From a key (a pair of two
uint16_t) I need to provide extra information. Think of it as a yellow
page, from an integer I need to provide a char array (the name).

template <int Numberstruct YellowPage;
template <struct YellowPage<1234567890{
enum { Age = 33 };
static const char Name[];
void Print(std::ostream &os) { os << Name << " is " << Age << " old
\n"; }
};
const char YellowPage<1234567890>::Name[] = "John Doe";

int main()
{
YellowPage<1234567890jd;
jd.Print( std::cout );
return 0;
}

Actually I do even need to expose the 'Name', all I need is really the
'Print' function (to an ostream).
From your last post, I understood that there is no way to initialize
data, enum were just a special case. Maybe with some ifdef blockers
magic, I should be able to include only once the initilization part...

Thanks
-Mathieu

re: initialization of static data member in header file

On Feb 11, 4:29 pm, mathieu <mathieu.malate...@gmail.comwrote:How about simply:

template <int Numberstruct YellowPage;
template <struct YellowPage<1234567890{
enum { Age = 33 };
const char *GetName() const {
static const char Name[] = "John Doe";
return Name;
}
void Print(std::ostream &os) { os << GetName() << " is " << Age << "
years old\n"; }
};

that should do it.

Thanks all, and sorry for the noise
-Mathieu

re: initialization of static data member in header file

On Feb 11, 4:51 pm, mathieu <mathieu.malate...@gmail.comwrote:Afterall I needed this one:

static const char *GetName() { return "John Doe"; }

-M