Module cdyn 

cdyn — COM-style C function-table loading (ABI-stable)

Load Copy-sized vtable/descriptor structs from dynamic libraries using plain C function tables — no Rust trait objects, no named-based access, purely positional dispatch. This is the COM+-like emulated vtable system (formerly the separate cdyn-loader crate).

Unlike crate::dyn_mod, this mode is ABI-stable across languages: the C++ SDK (cdyn-loader-sdks/cpp) and Zig SDK (cdyn-loader-sdks/zig) build plugins that match these layouts exactly.

Cross-module memory ownership model

The core of every cross-module boundary is who manages memory. Every pointer crossing the boundary must be paired with a deallocation function that lives in the module which allocated the memory (allocators are not guaranteed to match across module/CRT boundaries). This crate provides three ownership tiers, all following that rule:

Tier	Type	Ownership	Free function
Stateless	VTablePlugin<T>	none (static vtable)	—
Instance (multi-owner)	CdynHandle<T>	ref-counted via retain/release fn ptrs in AbiStableDynRef	provided by the plugin
Data (single-owner)	CdynBox / CdynBoxHandle	move-only, exactly one owner	free fn ptr in the box, provided by the allocating module

Cross-module safety rules enforced by construction:

1. Allocator symmetry — free/release always execute inside the module that allocated (the function pointer belongs to that module’s code, e.g. CdynBox::from_vec pairs with a Rust-plugin allocator).
2. Library lifetime — CdynBoxHandle and CdynHandle<T> own a DynLib (Arc-shared), so the library cannot be unloaded while a handle (and thus a free/release fn ptr) still exists.

Usage

#[repr(C)]
struct MyVtable {
    add: unsafe extern "C" fn(i32, i32) -> i32,
    name: unsafe extern "C" fn() -> *const std::ffi::c_char,
}

let plugin = unsafe { VTablePlugin::<MyVtable>::load("libmy.so", b"my_get_vtable\0")? };
let n = unsafe { (plugin.vtable().add)(1, 2) };

Structs

CdynBox

A cross-module data box: memory allocated and freed by the same module.

CdynBoxHandle

Host-side owning handle over a CdynBox received from a foreign module.

CdynHandle

Ref-counted handle to a foreign plugin object exposed through a *_get_dyn style entry point returning an AbiStableDynRef.

GeneratedFunction

Descriptor for a generated math function (matches C++ GeneratedFunction)

MathModuleVtable

Vtable struct matching C++ MathModuleVtable layout exactly

VTablePlugin

Load a Copy-sized vtable/descriptor struct from a dynamic library.

Functions

cdyn_box_free_rust^⚠

Rust plugin free function paired with CdynBox::from_vec.

Type Aliases

MathSession

Opaque handle for a C++ MathSession

PluginDynEntryPoint

Type of the dyn entry point that foreign plugins export (C++ CDYN_EXPORT AbiStableDynRef name_get_dyn(), Zig declareDynEntry).