const struct stat64 *st);
/*
+ * Function called to report an error during scanning. The ctx is
+ * the same one passed to gotdata_fn_t.
+ */
+typedef void (*err_fn_t)(void *vctx, const char *fmt, ...);
+
+/*
* Recursively scan a directory tree and report every
* space-consuming item in it to gotdata().
*/
-void du(char *path, gotdata_fn_t gotdata, void *gotdata_ctx);
+void du(const char *path, gotdata_fn_t gotdata, err_fn_t err,
+ void *gotdata_ctx);