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Command: timer_create | Section: 3 | Source: Digital UNIX | File: timer_create.3.gz
timer_create(3) Library Functions Manual timer_create(3)
NAME
timer_create - Allocate a per-process timer
SYNOPSIS
#include <signal.h> #include <time.h>
int timer_create ( clockid_t clock_id, struct sigevent *evp,
timer_t *timerid );
PARAMETERS
The type of clock on which the timer is based. The CLOCK_REALTIME clock
is supported. A pointer to a sigevent structure, which defines the
signal sent to the process on timer expiration. 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 spec-
ified clock as the timing base. The timer_create function returns
timer_id, which is used to identify 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 will occur when the timer
expires. If the sigev_notify member of evp is SIGEV_SIGNAL, the struc-
ture must contain the signal number and data value to send to the
process when the timer expires. If the sigev_notify member is
SIGEV_NONE, no notification will be sent.
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 de-
fined in the <sys/rt_limits.h> header file, which is indirectly in-
cluded through <time.h>.
Timers are not inherited across fork calls. An exec call will disarm
and delete a timer.
RETURN VALUES
Upon successful completion, a value of 0 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.
RELATED INFORMATION
Functions: clock_getres(3), clock_gettime(3), clock_settime(3),
timer_delete(3), timer_gettime(3), timer_settime(3) delim off
timer_create(3)