* to use an fd-tracker.
*/
-typedef int (*fs_handle_get_fd_cb)(struct fs_handle *);
-typedef void (*fs_handle_put_fd_cb)(struct fs_handle *);
-typedef int (*fs_handle_unlink_cb)(struct fs_handle *);
-typedef int (*fs_handle_close_cb)(struct fs_handle *);
+using fs_handle_get_fd_cb = int (*)(struct fs_handle *);
+using fs_handle_put_fd_cb = void (*)(struct fs_handle *);
+using fs_handle_unlink_cb = int (*)(struct fs_handle *);
+using fs_handle_close_cb = int (*)(struct fs_handle *);
struct fs_handle {
fs_handle_get_fd_cb get_fd;