uuid_clear(3uuid)

1uuid_clear(3UUID)Universally Unique Identifier Library Functionusuid_clear(3UUID)
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NAME

6       uuid_clear,  uuid_compare, uuid_copy, uuid_generate, uuid_generate_ran‐
7       dom,   uuid_generate_time,   uuid_is_null,    uuid_parse,    uuid_time,
8       uuid_unparse - universally unique identifier (UUID) operations
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SYNOPSIS

11       cc [ flag ... ] file... -luuid [ library ... ]
12       #include <uuid/uuid.h>
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14       void uuid_clear(uuid_t uu);
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17       int uuid_compare(uuid_t uu1, uuid_t uu2);
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20       void uuid_copy(uuid_t dst, uuid_t src);
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23       void uuid_generate(uuid_t out);
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26       void uuid_generate_random(uuid_t out);
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29       void uuid_generate_time(uuid_t out);
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32       int uuid_is_null(uuid_t uu);
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35       int uuid_parse(char *in, uuid_t uu);
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38       time_t uuid_time(uuid_t uu, struct timeval *ret_tv);
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41       void uuid_unparse(uuid_t uu, char *out);
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DESCRIPTION

45       The  uuid_clear()  function sets the value of the specified universally
46       unique identifier (UUID) variable uu to the NULL value.
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49       The uuid_compare() function compares the two specified  UUID  variables
50       uu1  and  uu2 to each other. It returns an integer less than, equal to,
51       or greater than zero if uu1 is found to be, respectively, lexicographi‐
52       cally less than, equal, or greater than uu2.
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55       The uuid_copy() function copies the UUID variable src to dst.
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58       The uuid_generate() function creates a new UUID that is generated based
59       on  high-quality  randomness  from  /dev/urandom,  if   available.   If
60       /dev/urandom   is  not  available,  uuid_generate()  calls  uuid_gener‐
61       ate_time(). Because the use  of  this  algorithm  provides  information
62       about  when  and  where  the UUID was generated, it could cause privacy
63       problems for some applications.
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66       The uuid_generate_random() function produces a UUID with  a  random  or
67       pseudo-randomly  generated  time  and  Ethernet MAC address that corre‐
68       sponds to a DCE version 4 UUID.
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71       The uuid_generate_time() function uses the current time and  the  local
72       Ethernet  MAC  address (if available, otherwise a MAC address is fabri‐
73       cated) that corresponds to a DCE version 1 UUID. If  the  UUID  is  not
74       guaranteed  to  be unique, the multicast bit is set (the high-order bit
75       of octet number 10).
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78       The uuid_is_null() function compares the value of  the  specified  UUID
79       variable  uu to the NULL value. If the value is equal to the NULL UUID,
80       1 is returned. Otherwise 0 is returned.
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83       The uuid_parse() function converts the UUID string specified by  in  to
84       the  internal  uuid_t  format.  The  input UUID is a string of the form
85       cefa7a9c-1dd2-11b2-8350-880020adbeef. In printf(3C) format, the  string
86       is "%08x-%04x-%04x-%04x-%012x", 36 bytes plus the trailing null charac‐
87       ter. If the input string is parsed successfully, 0 is returned and  the
88       UUID  is  stored  in  the  location  pointed  to by uu. Otherwise -1 is
89       returned.
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92       The uuid_time() function extracts the time at which the specified  UUID
93       uu  was  created.  Since  the  UUID creation time is encoded within the
94       UUID, this function can reasonably be expected to extract the  creation
95       time only for UUIDs created with the uuid_generate_time() function. The
96       time at which the UUID was created, in seconds since  January  1,  1970
97       GMT  (the epoch), is returned (see time(2)). The time at which the UUID
98       was created, in seconds and microseconds since the epoch is also stored
99       in the location pointed to by ret_tv (see gettimeofday(3C)).
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102       The  uuid_unparse()  function  converts  the specified UUID uu from the
103       internal binary format to a string of the length defined in the  uuid.h
104       macro,  UUID_PRINTABLE_STRING_LENGTH,  which includes the trailing null
105       character. The resulting  value  is  stored  in  the  character  string
106       pointed to by out.
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ATTRIBUTES

109       See attributes(5) for descriptions of the following attributes:
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114       ┌─────────────────────────────┬─────────────────────────────┐
115       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
116       ├─────────────────────────────┼─────────────────────────────┤
117       │Interface Stability          │Evolving                     │
118       ├─────────────────────────────┼─────────────────────────────┤
119       │MT-Level                     │Safe                         │
120       └─────────────────────────────┴─────────────────────────────┘
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NAME

SYNOPSIS

DESCRIPTION

ATTRIBUTES

SEE ALSO