{{#title Function pointers — Rust ♡ C++}}

Function pointers

Public API:

// rust/cxx.h
...
...namespace rust {

template <typename Signature>
class Fn;

template <typename Ret, typename... Args>
class Fn<Ret(Args...)> final {
public:
  Ret operator()(Args... args) const noexcept;
  Fn operator*() const noexcept;
};
...
...} // namespace rust

Restrictions:

Function pointers with a Result return type are not implemented yet.

Passing a function pointer from C++ to Rust is not implemented yet, only from Rust to an extern "C++" function is implemented.

Example

Function pointers are commonly useful for implementing async functions over FFI. See the example code on that page.