On 4/2/20 3:35 PM, Thomas Gleixner wrote: > "Michael Kerrisk (man-pages)" <mtk.manpages@xxxxxxxxx> writes: >> NOTES >> Suppose the following scenario for CLOCK_REALTIME or CLOCK_REAL‐ >> TIME_ALARM timer that was created with timerfd_create(): >> >> (a) The timer has been started (timerfd_settime()) with the >> TFD_TIMER_ABSTIME and TFD_TIMER_CANCEL_ON_SET flags; >> >> (b) A discontinuous change (e.g. settimeofday(2)) is subsequently >> made to the CLOCK_REALTIME clock; and >> >> (c) the caller once more calls timerfd_settime() to rearm the >> timer (without first doing a read(2) on the file descriptor). >> >> In this case the following occurs: >> >> · The timerfd_settime() returns -1 with errno set to ECANCELED. >> (This enables the caller to know that the previous timer was >> affected by a discontinuous change to the clock.) >> >> · The timer is successfully rearmed with the settings provided in >> the second timerfd_settime() call. (This was probably an imple‐ >> mentation accident, but won't be fixed now, in case there are >> applications that depend on this behaviour.) > > Clear enough. > > Thanks Michael! Thanks. Committed. (But, next time you change the API. maybe a man-pages patch to go with that? :-).) Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/
