C++ lambda - capture static member variable

Question

I have a lambda function inside a static class method, like so:

void
MyClass::foo() {
  auto my_lambda = [](int arg) {
    // do stuff
  }
}

Where foo is a static method of MyClass. Now, inside my_lambda I want to reference another static method bar of MyClass. How can I do this? I've seen this question but it seems like this only works for non static methods, since static methods cannot reference this?

How can I do this? Just like you would anywhere else. `ClassName::StaticFunctionName(Parameters);` — NathanOliver, Nov 22 '19 at 21:33
What did you actually try? Simply calling `bar` works as expected since it's a static method. No need to capture anything. — super, Nov 22 '19 at 21:39
title doesn't match content.. static method is a global function, static variable is a little different, but both are available through name? — Swift - Friday Pie, Nov 22 '19 at 21:54
You don't need `this` to accesses a static method. So simply capture the normal way. — Martin York, Nov 22 '19 at 22:26

score 0 · Answer 1 · answered Nov 22 '19 at 22:50

Here's my naive take on it - but I may have misunderstood the question.

#include <iostream>

class MyClass {
private:
    static int variable;                                // just some common data

public:
    static void another(int dest) {                     // receiver
        std::cout << "I'm alive: " << dest << "\n"; 
    }
    static void foo();
};

int MyClass::variable = 4;                              // 

void MyClass::foo() {
    auto my_lambda = [](int arg) {
        another(arg + variable);                        // reference another static method
    };
    my_lambda(123);
}

int main() {
    MyClass apa;

    apa.foo();
}

I'm alive: 127

C++ lambda - capture static member variable

1 Answers1