I want to implement a member function as follows:
void X() {}
class Foo
{
static void(*Bar)() = X;
};
This does not compile:
error: 'constexpr' needed for in-class initialization of static data member 'void (* Foo::Bar)()' of non-integral type
I know this is not legal. I have to either initialize Bar outside of the class scope or make it "inline static". The problem is that the latter is a C 17 feature and I must do with C 11 (BCC32X limitations). So my question is: Is there a way to do this on the same line? Maybe making it const? I know we can do this(Source)...
class Foo
{
static int const i = 42;
}
But can we apply it to functions somehow?
PD: I know there are infinite solutions to my question all over SO, but up until now all I've seen end up relying on later C features not available to me.
CodePudding user response:
Since C 11 you can use constexpr
to initialize static members of non-integral/enumeration types in the class declaration.
As @paddy comments below, this makes Bar
const so it would only be a viable solution if you don't plan to modify it, what you are not doing in the question's code.
#include <iostream> // cout
void X() {
std::cout << "Blah\n";
}
struct Foo {
static constexpr void(*Bar)() = X;
};
int main() {
Foo::Bar();
}