UUID_CLEAR(3UUID) Universally Unique Identifier Library Functions
NAME
uuid_clear,
uuid_compare,
uuid_copy,
uuid_generate,
uuid_generate_random,
uuid_generate_time,
uuid_is_null,
uuid_parse,
uuid_time,
uuid_unparse,
uuid_unparse_lower,
uuid_unparse_upper - universally unique identifier
(UUID) operations
LIBRARY
UUID Library (libuuid, -luuid)
SYNOPSIS
#include <uuid/uuid.h> void uuid_clear(
uuid_t uu);
int uuid_compare(
uuid_t uu1,
uuid_t uu2);
void uuid_copy(
uuid_t dst,
uuid_t src);
void uuid_generate(
uuid_t out);
void uuid_generate_random(
uuid_t out);
void uuid_generate_time(
uuid_t out);
int uuid_is_null(
uuid_t uu);
int uuid_parse(
char *int,
uuid_t uu);
time_t uuid_time(
uuid_t uu,
struct timeval *ret_tv);
void uuid_unparse(
uuid_t uu,
char *out);
void uuid_unparse_lower(
uuid_t uu,
char *out);
void uuid_unparse_upper(
uuid_t uu,
char *out);
DESCRIPTION
The
uuid_clear() function sets the value of the specified universally
unique identifier (UUID) variable
uu to the NULL value.
The
uuid_compare() function compares the two specified UUID variables
uu1 and
uu2 to each other. It returns an integer less than, equal to, or
greater than zero if
uu1 is found to be, respectively, lexicographically
less than, equal, or greater than
uu2.
The
uuid_copy() function copies the UUID variable
src to
dst.
The
uuid_generate() and
uuid_generate_random() functions create a new UUID
that is generated based on high-quality randomness utilizing the
arc4random(3C) function. These correspond to a DCE version 4 UUID. On
some implementations it is possible that the
uuid_generate() function will
fall back to generating a version 1 UUID. While in our current
implementation this is not possible, applications should not assume a
guaranteed format when calling the
uuid_generate() function.
The
uuid_generate_time() function uses the current time and the local
Ethernet MAC address (if available, otherwise a MAC address is fabricated)
that corresponds to a DCE version 1 UUID. If the UUID is not guaranteed to
be unique, the multicast bit is set (the high-order bit of octet number
10).
The
uuid_is_null() function compares the value of the specified UUID
variable
uu to the NULL value. If the value is equal to the NULL UUID,
1 is returned. Otherwise
0 is returned.
The
uuid_parse() function converts the UUID string specified by
in to the
internal
uuid_t format. The input UUID is a string of the form
cefa7a9c-1dd2-11b2-8350-880020adbeef. In
printf(3C) format, the string is
"
%08x-%04x-%04x-%04x-%012x", 36 bytes plus the trailing null character. If
the input string is parsed successfully,
0 is returned and the UUID is
stored in the location pointed to by
uu. Otherwise
-1 is returned.
The
uuid_time() function extracts the time at which the specified UUID
uu was created. Since the UUID creation time is encoded within the UUID, this
function can reasonably be expected to extract the creation time only for
UUIDs created with the
uuid_generate_time() function. The time at which
the UUID was created, in seconds since January 1, 1970 GMT (the epoch), is
returned (see
time(2)). The time at which the UUID was created, in seconds
and microseconds since the epoch is also stored in the location pointed to
by
ret_tv (see
gettimeofday(3C)).
The
uuid_unparse() and
uuid_unparse_lower() functions convert the specified
UUID
uu from the internal binary format to a lower case string of the
length defined in the <
uuid/uuid.h> macro, UUID_PRINTABLE_STRING_LENGTH,
which includes the trailing null character. The resulting value is stored
in the character string pointed to by
out.
The uuid_unparse_upper function converts the specified UUID
uu from the
internal binary format to a upper case string of the length defined in the
<
uuid/uuid.h> macro, UUID_PRINTABLE_STRING_LENGTH, which includes the
trailing null character. The resulting value is stored in the character
string pointed to by
out.
INTERFACE STABILITY
EvolvingMT-LEVEL SafeSEE ALSO
time(2),
arc4random(3C),
gettimeofday(3C),
printf(3C),
libuuid(3LIB),
attributes(7)illumos November 30, 2021 illumos