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Diffstat (limited to 'lib/uuid/uuid_generate.3.in')
| -rw-r--r-- | lib/uuid/uuid_generate.3.in | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/lib/uuid/uuid_generate.3.in b/lib/uuid/uuid_generate.3.in new file mode 100644 index 0000000..e6be968 --- /dev/null +++ b/lib/uuid/uuid_generate.3.in @@ -0,0 +1,104 @@ +.\" Copyright 1999 Andreas Dilger (adilger@enel.ucalgary.ca) +.\" +.\" %Begin-Header% +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, and the entire permission notice in its entirety, +.\" including the disclaimer of warranties. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. The name of the author may not be used to endorse or promote +.\" products derived from this software without specific prior +.\" written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED +.\" WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES +.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF +.\" WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE +.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR +.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT +.\" OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR +.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF +.\" LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE +.\" USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH +.\" DAMAGE. +.\" %End-Header% +.\" +.\" Created Wed Mar 10 17:42:12 1999, Andreas Dilger +.TH UUID_GENERATE 3 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@" +.SH NAME +uuid_generate, uuid_generate_random, uuid_generate_time \- create a new unique UUID value +.SH SYNOPSIS +.nf +.B #include <uuid/uuid.h> +.sp +.BI "void uuid_generate(uuid_t " out ); +.BI "void uuid_generate_random(uuid_t " out ); +.BI "void uuid_generate_time(uuid_t " out ); +.fi +.SH DESCRIPTION +The +.B uuid_generate +function creates a new universally unique identifier (UUID). The uuid will +be generated based on high-quality randomness from +.IR /dev/urandom , +if available. If it is not available, then +.B uuid_generate +will use an alternative algorithm which uses the current time, the +local ethernet MAC address (if available), and random data generated +using a pseudo-random generator. +.sp +The +.B uuid_generate_random +function forces the use of the all-random UUID format, even if +a high-quality random number generator (i.e., +.IR /dev/urandom ) +is not available, in which case a pseudo-random +generator will be substituted. Note that the use of a pseudo-random +generator may compromise the uniqueness of UUID's +generated in this fashion. +.sp +The +.B uuid_generate_time +function forces the use of the alternative algorithm which uses the +current time and the local ethernet MAC address (if available). +This algorithm used to be the default one used to generate UUID, but +because of the use of the ethernet MAC address, it can leak +information about when and where the UUID was generated. This can cause +privacy problems in some applications, so the +.B uuid_generate +function only uses this algorithm if a high-quality source of +randomness is not available. +.sp +The UUID is 16 bytes (128 bits) long, which gives approximately 3.4x10^38 +unique values (there are approximately 10^80 elementary particles in +the universe according to Carl Sagan's +.IR Cosmos ). +The new UUID can reasonably be considered unique among all UUIDs created +on the local system, and among UUIDs created on other systems in the past +and in the future. +.SH RETURN VALUE +The newly created UUID is returned in the memory location pointed to by +.IR out . +.SH "CONFORMING TO" +OSF DCE 1.1 +.SH AUTHOR +Theodore Y. Ts'o +.SH AVAILABILITY +.UR http://e2fsprogs.sourceforge.net/ +http://e2fsprogs.sourceforge.net/ +.UE +.SH "SEE ALSO" +.BR uuid (3), +.BR uuidgen (1), +.BR uuid_clear (3), +.BR uuid_compare (3), +.BR uuid_copy (3), +.BR uuid_is_null (3), +.BR uuid_parse (3), +.BR uuid_time (3), +.BR uuid_unparse (3) |