RAII Handle System #

The unique_handle<T, Deleter> template in wolfram-cpp/wolfram/unique_handle.hpp provides a lightweight, type‑safe wrapper around C resources. It behaves like std::unique_ptr but is header‑only and has no external dependencies.

Usage #

#include "wolfram-cpp/wolfram/wolfram.hpp"

// Acquire a C resource
wf_actor *actor = wf_actor_new();

// Wrap it in a unique_handle
using actor_handle = unique_handle<wf_actor, wf_actor_free>;
actor_handle a(actor);

// Use the resource
wf_status st = wf_actor_get_did(a.get());

// No manual free needed – a is destroyed automatically

Advantages #

• No manual free – the deleter is called automatically when the handle goes out of scope.
• Exception safety – the deleter is invoked even if an exception propagates.
• Zero runtime overhead – the wrapper is a thin struct with a single pointer.
• Explicit ownership – the type clearly indicates that the caller owns the resource.

Supported Types #

The wrapper is instantiated for every public C type that has a matching *_free function. The generated header generated_owners.hpp contains the following typedefs:

using wf_actor_handle = unique_handle<wf_actor, wf_actor_free>;
using wf_repo_handle  = unique_handle<wf_repo, wf_repo_free>;
// …

These can be used directly in C++ code.

Note: The C++ layer is header‑only; it does not add any new runtime dependencies beyond the existing C library.