1CLOCK_NANOSLEEP(2)         Linux Programmer's Manual        CLOCK_NANOSLEEP(2)
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NAME

6       clock_nanosleep - high-resolution sleep with specifiable clock
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SYNOPSIS

9       #include <time.h>
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11       int clock_nanosleep(clockid_t clock_id, int flags,
12                           const struct timespec *request,
13                           struct timespec *remain);
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15       Link with -lrt.
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17   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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19       clock_nanosleep(): _XOPEN_SOURCE >= 600
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DESCRIPTION

22       Like  nanosleep(2), clock_nanosleep() allows the caller to sleep for an
23       interval specified with nanosecond precision.  It differs  in  allowing
24       the  caller  to select the clock against which the sleep interval is to
25       be measured, and in allowing the sleep  interval  to  be  specified  as
26       either an absolute or a relative value.
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28       The time values passed to and returned by this call are specified using
29       timespec structures, defined as follows:
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31           struct timespec {
32               time_t tv_sec;        /* seconds */
33               long   tv_nsec;       /* nanoseconds [0 .. 999999999] */
34           };
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36       The clock_id argument specifies  the  clock  against  which  the  sleep
37       interval  is to be measured.  This argument can have one of the follow‐
38       ing values:
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40       CLOCK_REALTIME   A settable system-wide real-time clock.
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42       CLOCK_MONOTONIC  A nonsettable,  monotonically  increasing  clock  that
43                        measures time since some unspecified point in the past
44                        that does not change after system startup.
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46       CLOCK_PROCESS_CPUTIME_ID
47                        A settable per-process clock that  measures  CPU  time
48                        consumed by all threads in the process.
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50       See clock_getres(2) for further details on these clocks.
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52       If flags is 0, then the value specified in request is interpreted as an
53       interval relative to the  current  value  of  the  clock  specified  by
54       clock_id.
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56       If  flags  is TIMER_ABSTIME, then request is interpreted as an absolute
57       time as measured by the clock, clock_id.  If request is  less  than  or
58       equal to the current value of the clock, then clock_nanosleep() returns
59       immediately without suspending the calling thread.
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61       clock_nanosleep() suspends the execution of the  calling  thread  until
62       either  at least the time specified by request has elapsed, or a signal
63       is delivered that causes a signal handler to be called or  that  termi‐
64       nates the process.
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66       If  the  call  is  interrupted  by  a signal handler, clock_nanosleep()
67       returns -1, and sets errno to EINTR.  In addition,  if  remain  is  not
68       NULL, and flags was not TIMER_ABSTIME, it returns the remaining unslept
69       time in remain.  This value can then be used to call  clock_nanosleep()
70       again and complete a (relative) sleep.
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RETURN VALUE

73       On  successfully sleeping for the requested interval, clock_nanosleep()