Function value_incref 

pub unsafe extern "C" fn value_incref(
    context: *mut c_context,
    value: *mut value,
) -> err

@brief Increment the garbage collector reference counter for the given nix_value. @ingroup value

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

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