How to convert a Rust closure to a C-style callback?

[mhanusek]

I'm trying to write a simple wrapper.

How would I wrap a callback without getting "can't capture dynamic environment in a fn item"?

Hi! I need to do some stuff, like converting and processing strings, before returning from a callback. This is how i would usually do it in javascript: let cb = () => "Hello"; function register_cb(cb) { document.onBlahBlahBlah(() => cb() + "world!"); } register_cb(cb); // output(when cb is called): "Hello world!" But when I try to do a similar thing in rust: use std::slice; static CONTENT: &'static str = include_str!("../../test.html"); extern "C" { fn env_register_on_connection…

pub type CCallback = unsafe extern "C" fn( *mut c_void ) -> STATUS_T;

pub fn function_rust<F: Fn()>(myfunc: F, handle : &mut HANDLE_t)
{
    unsafe extern "C" fn wrapper<F: Fn()>( args : *mut c_void ) -> STATUS_T
    {
        myfunc();
        println!("wrapper");
        STATUS_T::OK
    };

    c_func_set_cb(wrapper::<F>).unwrap();
}

///...

///Call
   function_rust(||{
        println!("TEST");
    },  &mut v.handle);

Error:

error[E0434]: can't capture dynamic environment in a fn item
  --> src/lib.rs:90:9
   |
90 |         myfunc();
   |         ^^^^^^
   |
   = help: use the `|| { ... }` closure form instead