--- a/src/lib/str.h	Wed May 27 23:57:48 2009 +0300
+++ b/src/lib/str.h	Thu May 28 00:35:02 2009 +0300
@@ -20,6 +20,7 @@
     ERR_STR_FMT_NAME,               ///< invalid/unknown parameter name
     ERR_STR_FMT_FLAGS_LEN,          ///< invalid paramter flags length
     ERR_STR_FMT_FLAG,               ///< invalid paramter flag
+    ERR_STR_FMT_VALUE,              ///< parameter value
     ERR_STR_FMT_BUF_LEN,            ///< output buffer ran out
 };
 
@@ -104,9 +105,9 @@
  * @param value returned pointer to param value
  * @param value_len returned param value length, or -1 for strlen
  * @param arg the context arg given to str_format
- * @return the parameter value, or NULL to error out
+ * @param err returned error info
  */
-typedef err_t (*str_format_cb) (const char *name, const char **value, ssize_t *value_len, void *arg);
+typedef err_t (*str_format_cb) (const char *name, const char **value, ssize_t *value_len, void *arg, error_t *err);
 
 /**
  * Maximum length of a parameter name