Template Function Parameter

Question

edit: Solved. Was just a stupid order of definition mistake....

So I have a function that looks like this, in the header of a class called Action:

template <class Attacker, class Defender>
static int attack_result (Attacker A, Defender D) {
    //<snip>

    if (random(100) < res)
        return 1;

    //etc.
}

And I get this when compiling:

error: there are no arguments to 'random' that depend on a template parameter, so a declaration of 'random' must be available note: (if you use '-fpermissive', G++ will accept your code, but allowing the use of an undeclared name is deprecated)

The function random() is declared in a static class called Global like this:

extern float random(int);

I'm calling Action::attack_result(...) from classes called NPC and Player, both of which are derived from a class called Creature. I don't think that's vital information, but I'll mention it in case it is. The parameters for Action::attack_result are both of Creature class.

I get why this error is being thrown, but I'm not sure how to fix it. I tried declaring Global in the Action header, I tried messing around with the keyword "using"...I can't go like this:

if (this->random(100) < res)

Because I get the following error (Creature, NPC, Player are static [and must be]):

error: 'this' is unavailable for static member functions

Going Global::random(100) does not work either:

error: incomplete type 'Global' used in nested name specifier

Any help would be very useful.

If random is a static member function of Global, then you should be able to call it with if(Global::random(100) < res). Did you mean to make random a static member function rather than an extern function? — Jared Hoberock
– Jared Hoberock, Commented Aug 15, 2011 at 4:57
@Matthew: Do not mutilate this question if you got a solution, rather accept the good solution. — Benjamin Bannier
– Benjamin Bannier, Commented Aug 15, 2011 at 6:40
Do not mutilate this question if you do not have a problem anymore. Instead, you can answer to your own question with your fix and accept that. StackOverflow is not a chat; ideally your questions and its answers can help others in the future. 'Blanking' the question defeats that purpose. — Luc Danton
– Luc Danton, Commented Aug 15, 2011 at 7:15

sashang · Accepted Answer · 2011-08-15 04:59:20Z

1

Sounds like random is in the Gloabl namespace so you need to call it like this Global::random.

answered Aug 15, 2011 at 4:59

sashang

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2 Comments

Matthew Over a year ago

error: incomplete type 'Global' used in nested name specifier

Mike DeSimone Over a year ago

That means it can see a class Global; declaration but no class Global { ... }; definition. Check your #include list.

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