#include <coroutine>
#include <cstdio>

struct coro
{
    struct promise_type
    {
        coro get_return_object() { return {}; }
        std::suspend_never initial_suspend() noexcept { return {}; }
        std::suspend_never final_suspend() noexcept { return {}; }
        void return_void() {}
        void unhandled_exception() {}
    };
};

coro f(const char *arg)
{
    std::puts(arg);
    co_return; // requiere return_void() en promise_type
}

int main(int argc, char *argv[]) { f(argv[0]); }