UUID_GENERATE(3) UUID_GENERATE(3) uuid_generate, uuid_generate_random, uuid_generate_time, uuid_generate_time_safe - UUID #include void uuid_generate(uuid_t out); void uuid_generate_random(uuid_t out); void uuid_generate_time(uuid_t out); int uuid_generate_time_safe(uuid_t out); void uuid_generate_md5(uuid_t out, const uuid_t ns, const char *name, size_t len); void uuid_generate_sha1(uuid_t out, const uuid_t ns, const char *name, size_t len); uuid_generate() (UUID) . uuid getrandom(2) /dev/urandom /dev/random . uuid_generate() MAC ( ) . uuid_generate_random(3) UUID . UUID . uuid_generate_time(3) MAC ( ). UUID MAC UUID. uuid_generate() . UUID uuid ( ) / uuidd(8) ( ). UUID. UUID uuid_generate_time_safe(3). uuid_generate_time_safe(3) uuid_generate_time(3) ( ) . UUID 16 (128 ) 3.4x10^38 ( 10^80 Cosmos ). . uuid_generate_md5(3) uuid_generate_sha1(3) UUID MD5 SHA1 () UUID . UUID V3 V5 UUID RFC-4122 . UUID out. uuid_generate_time_safe(3) UUID -1 . UUID OSF DCE 1.1 UUID V3 V5 RFC-4122 . Theodore Y. Ts'o uuidgen(1) uuid(3) uuid_clear(3) uuid_compare(3) uuid_copy(3), uuid_is_null(3) uuid_parse(3) uuid_time(3) uuid_unparse(3) uuidd(8) . libuuid util-linux 2.15.1. . util-linux 2.42.1 2026-05-18 UUID_GENERATE(3)