-static int xbm_scan (unsigned char **, unsigned char *, char *, int *);
-static int xbm_load (struct frame *f, struct image *img);
-static int xbm_load_image (struct frame *f, struct image *img,
- unsigned char *, unsigned char *);
-static int xbm_image_p (Lisp_Object object);
-static int xbm_read_bitmap_data (struct frame *f,
- unsigned char *, unsigned char *,
- int *, int *, char **, int);
-static int xbm_file_p (Lisp_Object);
+static bool xbm_load (struct frame *f, struct image *img);
+static bool xbm_image_p (Lisp_Object object);
+static bool xbm_file_p (Lisp_Object);