+XBT_PUBLIC(void) xbt_cfg_register_double (xbt_cfg_t * cfg, const char *name, const char *desc, double default_val, xbt_cfg_cb_t cb_set);
+XBT_PUBLIC(void) xbt_cfg_register_int (xbt_cfg_t * cfg, const char *name, const char *desc, int default_val, xbt_cfg_cb_t cb_set);
+XBT_PUBLIC(void) xbt_cfg_register_string (xbt_cfg_t * cfg, const char *name, const char *desc, const char*default_val,xbt_cfg_cb_t cb_set);
+XBT_PUBLIC(void) xbt_cfg_register_boolean(xbt_cfg_t * cfg, const char *name, const char *desc, const char*default_val,xbt_cfg_cb_t cb_set);