#Set alarm time on dclock linux

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Set alarm time on dclock linux

#Set alarm time on dclock linux manual#

Using the appropriate macros, open file descriptors may be converted Such devices are called "dynamic" clocks, and are sup‐ In addition to the hard-coded System-V style clock IDs describedĪbove, Linux also supports POSIX clock operations on certain charac‐ Linux also implements dynamic clock instances as described below. On Linux, this clock is not settable.ĬLOCK_THREAD_CPUTIME_ID (since Linux 2.6.12) Process (i.e., CPU time consumed by all threads in the This is a clock that measures CPU time consumed by this See timer_create(2) for further details.ĬLOCK_PROCESS_CPUTIME_ID (since Linux 2.6.12) Ities if the time is changed using settimeofday(2) or similar.ĬLOCK_BOOTTIME_ALARM (since Linux 3.0 Linux-specific) Suspend-aware monotonic clock without having to deal with theĬomplications of CLOCK_REALTIME, which may have discontinu‐ This clockĭoes not count time that the system is suspended.ĬLOCK_BOOTTIME (since Linux 2.6.39 Linux-specific)Ī nonsettable system-wide clock that is identical toĬLOCK_MONOTONIC, except that it also includes any time that Incremental adjustments performed by adjtime(3). Ware-based time that is not subject to NTP adjustments or the Similar to CLOCK_MONOTONIC, but provides access to a raw hard‐ Ture support for this flag in the vdso(7).ĬLOCK_MONOTONIC_RAW (since Linux 2.6.28 Linux-specific) Requires per-architecture support, and probably also architec‐ When you need very fast, but not fine-grained timestamps. May-depending on the architecture-return identical (not-ĬLOCK_MONOTONIC_COARSE (since Linux 2.6.32 Linux-specific)Ī faster but less precise version of CLOCK_MONOTONIC. AllĬLOCK_MONOTONIC variants guarantee that the time returned byĬonsecutive calls will not go backwards, but successive calls This clockĭoes not count time that the system is suspended. Tal adjustments performed by adjtime(3) and NTP. Manually changes the clock), but is affected by the incremen‐ Jumps in the system time (e.g., if the system administrator The CLOCK_MONOTONIC clock is not affected by discontinuous Onds that the system has been running since it was booted. On Linux, that point corresponds to the number of sec‐ Since-as described by POSIX-"some unspecified point in the The acronym TAI refers to International Atomic Time.Ī nonsettable system-wide clock that represents monotonic time This clock does not experienceĭiscontinuities and backwards jumps caused by NTP inserting Requires per-architecture support,Īnd probably also architecture support for this flag in theĬLOCK_TAI (since Linux 3.10 Linux-specific)Ī nonsettable system-wide clock derived from wall-clock timeīut ignoring leap seconds. Use when you need very fast, but notįine-grained timestamps. See timer_create(2)ĬLOCK_REALTIME_COARSE (since Linux 2.6.32 Linux-specific)Ī faster but less precise version of CLOCK_REALTIME. System time (e.g., if the system administrator manuallyĬhanges the clock), and by the incremental adjustments per‐ĬLOCK_REALTIME_ALARM (since Linux 3.0 Linux-specific) This clock is affected by discontinuous jumps in the Setting this clock requires appropriate privi‐ Sufficiently recent versions of glibc and the Linux kernel supportĪ settable system-wide clock that measures real (i.e., wall-Ĭlock) time. Sponding time values and the effect on timers is unspecified. Relative interval are unaffected, but timers for an absolute point in Processes, or per-process if it measures time only within a singleĪll implementations support the system-wide real-time clock, which is A clock may be system-wide and hence visible for all The clockid argument is the identifier of the particular clock on The res and tp arguments are timespec structures, as specified in The functions clock_gettime() and clock_settime() retrieve and set If the time value pointed to by the argument tp ofĬlock_settime() is not a multiple of res, then it is truncated to a On the implementation and cannot be configured by a particular Specified clock clockid, and, if res is non-NULL, stores it in the The function clock_getres() finds the resolution (precision) of the Link with -lrt (only for glibc versions before 2.17).įeature Test Macro Requirements for glibc (see feature_test_macros(7)):Ĭlock_getres(), clock_gettime(), clock_settime(): SYNOPSIS top #include int clock_getres(clockid_t clockid, struct timespec * res ) int clock_gettime(clockid_t clockid, struct timespec * tp ) int clock_settime(clockid_t clockid, const struct timespec * tp )

#Set alarm time on dclock linux manual#

CLOCK_GETRES(2) Linux Programmer's Manual CLOCK_GETRES(2) NAME topĬlock_getres, clock_gettime, clock_settime - clock and time functions