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| author | Lennart Poettering <lennart@poettering.net> | 2021-05-26 16:07:55 +0200 |
|---|---|---|
| committer | Lennart Poettering <lennart@poettering.net> | 2021-05-26 21:44:15 +0200 |
| commit | 6f7530929538b28cb41c289ad9cbced51848fc02 (patch) | |
| tree | c5c8dadaa66409750bce7be1a83fbfe7f085728f /man/sd_id128_randomize.xml | |
| parent | 997c2d5625c99ece6049539e0809804ca67940d6 (diff) | |
| download | systemd-6f7530929538b28cb41c289ad9cbced51848fc02.tar.gz | |
man: document that it is guaranteed that generated ID128 are never all-zero or all-one
This is the case because the ID128 we generate are all marked as v4 UUID
which requires that some bits are zero and others are one. Let's
document this so that people can rely on SD_ID128_NULL being a special
value for "uninitialized" that is always distinguishable from generated
UUIDs.
Diffstat (limited to 'man/sd_id128_randomize.xml')
| -rw-r--r-- | man/sd_id128_randomize.xml | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/man/sd_id128_randomize.xml b/man/sd_id128_randomize.xml index cf6ca7726f..0bc1d0abd8 100644 --- a/man/sd_id128_randomize.xml +++ b/man/sd_id128_randomize.xml @@ -42,8 +42,9 @@ <filename>/dev/urandom</filename> kernel random number generator.</para> - <para>Note that <function>sd_id128_randomize()</function> always - returns a UUID v4-compatible ID.</para> + <para>Note that <function>sd_id128_randomize()</function> always returns a UUID v4-compatible ID. It is + hence guaranteed that this function will never return the ID consisting of all zero or all one bits + (<constant>SD_ID128_NULL</constant>, <constant>SD_ID128_ALLF</constant>).</para> <para>For more information about the <literal>sd_id128_t</literal> type, see |