it doesn't copy the stack pointer, but it enumerates all variables you use and captures a reference to it (I think the &, as used in address-of and references kind of gives it away). [=] {} unsurprisingly captures by value.
Some compilers do warn when you return lambdas capturing local vars by reference, but it is not super reliable.
#include <functional>
#include <iostream>
std::function<void()> create_lambda(const int& x, const int& y) {
return [&] {
std::cout << "x: " << x << "\n";
std::cout << "y: " << y << "\n";
};
}
int main() {
int x = 5;
int y = 7;
const auto f = create_lambda(x, y);
f();
}