// Copyright (C) 2024 Rowan Hart // SPDX-License-Identifier: Apache-2.0 use ffi::ffi; extern "C" fn run_callback( callback: extern "C" fn(*mut std::ffi::c_void, i32, i32, i32) -> i32, data: *mut std::ffi::c_void, ) -> i32 { callback(data, 1, 2, 3) } #[derive(Debug, Clone, PartialEq, Eq)] struct Vec3 { x: i32, y: i32, z: i32, } #[ffi(from_ptr, self_ty = "*mut std::ffi::c_void")] impl Vec3 { #[ffi(arg(self), arg(rest))] fn add(&mut self, x: i32, y: i32, z: i32) -> i32 { self.x += x; self.y += y; self.z += z; self.x + self.y + self.z } } fn main() { let mut v = Vec3 { x: 1, y: 2, z: 3 }; run_callback(vec3::add, &mut v as *mut Vec3 as *mut _); assert_eq!(v, Vec3 { x: 2, y: 4, z: 6 }) }