Function store_real_path 

pub unsafe extern "C" fn store_real_path(
    context: *mut c_context,
    store: *mut Store,
    path: *mut StorePath,
    callback: get_string_callback,
    user_data: *mut c_void,
) -> err

@brief Get the physical location of a store path

A store may reside at a different location than its storeDir suggests. This situation is called a relocated store. Relocated stores are used during NixOS installation, as well as in restricted computing environments that don’t offer a writable /nix/store.

Not all types of stores support this operation.

@param[in] context Optional, stores error information @param[in] store nix store reference @param[in] path the path to get the real path from @param[in] callback called with the real path @param[in] user_data arbitrary data, passed to the callback when it’s called.