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timer_create(3)
NAME
  timer_create - Allocates a per-process timer

SYNOPSIS
  #include <signal.h>
  #include <time.h>

  int timer_create (
	  clockid_t clock_id,
	  struct sigevent *evp,
	  timer_t *timerid );

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

PARAMETERS
  clock_id
      The type of clock on which the timer is based. The CLOCK_REALTIME clock
      is supported.

  *evp
      A pointer to a sigevent structure, which defines the signal sent to the
      process on timer expiration.

  *timerid
      A pointer to the timer ID returned by the call to the timer_create
      function.

DESCRIPTION
  The timer_create function allocates a per-process timer using the specified
  clock as the timing base. The timer_create function returns timer_id, which
  identifies the timer in timer requests. The timer ID is unique within the
  calling process until the timer is deleted. The timer is unarmed when first
  returned from a call to timer_create. To arm the timer, use the
  timer_settime function.

  The evp argument, if non-NULL, points to a sigevent structure, which
  defines the asynchronous notification that occurs when the timer expires.
  If the sigev_notify member of evp is SIGEV_SIGNAL, the structure must
  contain the signal number and data value to send to the process when the
  timer expires.

  SIGALRM is the default signal for CLOCK_REALTIME if the evp argument is
  NULL.

  The maximum number of timers supported per process (TIMER_MAX) is defined
  in the <sys/rt_limits.h> header file, which is indirectly included through
  <time.h>.

  Timers are not inherited across fork calls. An exec call disarms and
  deletes a timer.

RETURN VALUES
  Upon successful completion, a value of 0 (zero) is returned. The
  timer_create function also returns, in timerid, a pointer to the timer ID
  that has been created.

  An unsuccessful call returns -1, and errno is set to indicate the error
  type.

ERRORS
  The timer_create function fails under the following conditions:

  [EAGAIN]
      The system lacks sufficient signal queuing resources to honor the
      request.	The calling process has already created all of the timers it
      is allowed.

  [EINVAL]
      The specified clock ID is not defined.

SEE ALSO
  Functions: clock_getres(3), clock_gettime(3), clock_settime(3),
  timer_delete(3), timer_gettime(3), timer_settime(3)

  Guide to Realtime Programming

Index for Section 3

Alphabetical listing for T

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