stupid question

[Flzw]

I have a class declared in a header file that has a static vector variable
which I get unresolved external errors when I try to access it, I understand
static members should be declared in cpp but how is it done in this case?
Couldn't find anything about that, hope I am clear enough, thanks for any
help.

 

[Martin Magnusson]

I have a class declared in a header file that has a static vector variable
which I get unresolved external errors when I try to access it, I understand
static members should be declared in cpp but how is it done in this case?

Like this:

// In X.hpp:
class X
{
static std::vector<int> v;
};

// In X.cpp:
std::vector<int> X::v;

/ martin

 

[Dietmar Kuehl]

I have a class declared in a header file that has a static vector variable
which I get unresolved external errors when I try to access it, I understand
static members should be declared in cpp but how is it done in this

case?

You *declared* the static member in your class. You have apparently
nowhere *defined* the member:

| // file: foo.hpp
| struct foo {
| static std::vector<int> bar; // declaration
| // ...
| };

| // file: foo.cpp
| #include "foo.hpp"
| std::vector<int> foo::bar; // definition

Of course, the header should be protected against mulitple inclusion
but this should highlight the needed definition.