XBT_PUBLIC(void *) xbt_lib_get_or_null(xbt_lib_t lib, const char *name,
int level);
XBT_PUBLIC(xbt_dictelm_t) xbt_lib_get_elm_or_null(xbt_lib_t lib, const char *key);
XBT_PUBLIC(void *) xbt_lib_get_level(xbt_dictelm_t elm, int level);
XBT_PUBLIC(void *) xbt_lib_get_or_null(xbt_lib_t lib, const char *name,
int level);
XBT_PUBLIC(xbt_dictelm_t) xbt_lib_get_elm_or_null(xbt_lib_t lib, const char *key);
XBT_PUBLIC(void *) xbt_lib_get_level(xbt_dictelm_t elm, int level);