Macro interoptopus::callback

macro_rules! callback {
    ($name:ident($($param:ident: $ty:ty),*) $(-> $rval:ty)?) => { ... };
}

Defines a callback type, akin to a fn f(T) -> R wrapped in an Option.

A named delegate will be emitted in languages supporting them, otherwise a regular function pointer. For details, please see the callbacks module.

Example

This defines a type MyCallback with a parameter slice returning an u8.

use interoptopus::callback;
use interoptopus::patterns::slice::FFISlice;

callback!(MyCallback(slice: FFISlice<u8>) -> u8);

The generated type definition similar to:

#[repr(transparent)]
pub struct MyCallback(Option<extern "C" fn(FFISlice<u8>) -> u8>);