Reference here:
https://pubs.opengroup.org/onlinepubs/009695399/functions/timer_create.html
DESCRIPTION
...
Each implementation shall define a set of clocks that can be
used as timing bases for per-process timers. All implementations
shall support a clock_id of CLOCK_REALTIME.
*** If the Monotonic Clock option is supported, implementations shall
support a clock_id of CLOCK_MONOTONIC. ***
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Change-Id: Ia8e7302ed4a7e9ec11a0059bd68e9674ea942001
Signed-off-by: chao.an <anchao@xiaomi.com>
723698c787