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clock_gettime(3)
NAME
  clock_gettime, clock_settime - Obtains or sets the time for the specified
  clock (P1003.1b)

SYNOPSIS
  #include <time.h>

  int clock_gettime (
  clockid_t clock_id,
  struct timespec *tp);

  int clock_settime (
  clockid_t clock_id,
  const struct timespec *tp);

LIBRARY
  Realtime Library (librt.so, librt.a)

PARAMETERS
  clock_id
      The clock type used to obtain the time for the clock that is set. The
      CLOCK_REALTIME clock is supported and represents the TIME-OF-DAY clock
      for the system.

  *tp A pointer to a timespec data structure.

DESCRIPTION
  The clock_gettime function returns the current time (in seconds and
  nanoseconds) for the specified clock. The clock_settime function sets the
  specified clock. The CLOCK_REALTIME clock measures the amount of time
  elapsed since 00:00:00:00 January 1, 1970 Greenwich Mean Time (GMT),
  otherwise known as the Epoch. Time values  that fall between two non-
  negative integer multiples of the resolution are truncated down to the
  smaller multiple of the resolution.

  You must have superuser privileges to use the clock_settime function.

RETURN VALUES
  On a successful call to the clock_gettime or clock_settime functions, a
  value of 0 (zero) is returned.

  On an unsuccessful call, a value of -1 is returned and errno is set to
  indicate that an error occurred.

ERRORS
  The clock_gettime and clock_settime functions fail under the following
  conditions:

  [EINVAL]
      The clock_id argument does not specify a known clock.  The value
      pointed to by the tp argument to the clock_settime function is outside
      the range for the given clock_id. The tp argument specified a
      nanosecond value less than zero or greater than or equal to 1000
      million.

  [EPERM]
      The requesting process does not have the appropriate privilege to set
      the specified clock.

SEE ALSO
  Functions: time(1), clock_getres(3), ctime(3), timer_gettime(3)

  Guide to Realtime Programming

Index for Section 3

Alphabetical listing for C

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