DEF_EXT_LIB_BUILTIN (BUILT_IN_ISASCII, "isascii", BT_FN_INT_INT, ATTR_CONST_NOTHROW_LIST)
DEF_C99_BUILTIN (BUILT_IN_ISBLANK, "isblank", BT_FN_INT_INT, ATTR_PURE_NOTHROW_LIST)
DEF_LIB_BUILTIN (BUILT_IN_ISCNTRL, "iscntrl", BT_FN_INT_INT, ATTR_PURE_NOTHROW_LIST)
-DEF_LIB_BUILTIN (BUILT_IN_ISDIGIT, "isdigit", BT_FN_INT_INT, ATTR_PURE_NOTHROW_LIST)
+DEF_LIB_BUILTIN (BUILT_IN_ISDIGIT, "isdigit", BT_FN_INT_INT, ATTR_CONST_NOTHROW_LIST)
DEF_LIB_BUILTIN (BUILT_IN_ISGRAPH, "isgraph", BT_FN_INT_INT, ATTR_PURE_NOTHROW_LIST)
DEF_LIB_BUILTIN (BUILT_IN_ISLOWER, "islower", BT_FN_INT_INT, ATTR_PURE_NOTHROW_LIST)
DEF_LIB_BUILTIN (BUILT_IN_ISPRINT, "isprint", BT_FN_INT_INT, ATTR_PURE_NOTHROW_LIST)
DEF_LIB_BUILTIN (BUILT_IN_ISPUNCT, "ispunct", BT_FN_INT_INT, ATTR_PURE_NOTHROW_LIST)
DEF_LIB_BUILTIN (BUILT_IN_ISSPACE, "isspace", BT_FN_INT_INT, ATTR_PURE_NOTHROW_LIST)
DEF_LIB_BUILTIN (BUILT_IN_ISUPPER, "isupper", BT_FN_INT_INT, ATTR_PURE_NOTHROW_LIST)
-DEF_LIB_BUILTIN (BUILT_IN_ISXDIGIT, "isxdigit", BT_FN_INT_INT, ATTR_PURE_NOTHROW_LIST)
+DEF_LIB_BUILTIN (BUILT_IN_ISXDIGIT, "isxdigit", BT_FN_INT_INT, ATTR_CONST_NOTHROW_LIST)
DEF_EXT_LIB_BUILTIN (BUILT_IN_TOASCII, "toascii", BT_FN_INT_INT, ATTR_CONST_NOTHROW_LIST)
DEF_LIB_BUILTIN (BUILT_IN_TOLOWER, "tolower", BT_FN_INT_INT, ATTR_PURE_NOTHROW_LIST)
DEF_LIB_BUILTIN (BUILT_IN_TOUPPER, "toupper", BT_FN_INT_INT, ATTR_PURE_NOTHROW_LIST)