Re: initialization of static data member in header file

From:

James Kanze <james.kanze@gmail.com>

Newsgroups:

comp.lang.c++

Date:

Tue, 12 Feb 2008 01:01:29 -0800 (PST)

Message-ID:

<00ef1c5e-d224-4785-95bd-71345d2faa1b@d4g2000prg.googlegroups.com>

On Feb 11, 4:08 pm, "Victor Bazarov" <v.Abaza...@comAcast.net> wrote:

mathieu wrote:

On Feb 11, 3:29 pm, "Victor Bazarov" <v.Abaza...@comAcast.net> wrote:

mathieu wrote:

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

template <int g, int e> struct Lookup;
template <> struct Lookup<0,0> {
// some typedef + enums definitions
static const char A;
};
const char Lookup<0,0>::A = "BLA";

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'.

Sorry I meant:

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

Define and initialise static data in a separate translation
unit. It's not a work-around. It's the only way to do it.

Ok. This might be naive, but I was able to do it with typdef and enum,

Not sure what you mean here. Any code sample?

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.

Static data are special beasts. You can definitely forgo
linking if all you have is code and it's all in templates.

Not if an explicit specialization is involved, as here.
Explicit specializations are really just normal classes with
funny names, and follow all of the rules of normal classes.

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