Function gc_incref 

pub unsafe extern "C" fn gc_incref(
    context: *mut c_context,
    object: *const c_void,
) -> err

@brief Increment the garbage collector reference counter for the given object.

The Nix language evaluator C API keeps track of alive objects by reference counting. When you’re done with a refcounted pointer, call nix_gc_decref().

@param[out] context Optional, stores error information @param[in] object The object to keep alive