Standard C Library Functions timer_settime(3C)
NAME
timer_settime, timer_gettime, timer_getoverrun - per-process
timersSYNOPSIS
#include
int timer_settime(timer_t timerid, int flags,
const struct itimerspec *restrict value, struct itimerspec *restrict ovalue);int timer_gettime(timer_t timerid, struct itimerspec *value);
int timer_getoverrun(timer_t timerid);
DESCRIPTION
The timer_settime() function sets the time until the next
expiration of the timer specified by timerid from theit_value member of the value argument and arm the timer if
the it_value member of value is non-zero. If the specified
timer was already armed when timer_settime() is called, this
call resets the time until next expiration to the valuespecified. If the it_value member of value is 0, the timer
is disarmed. The effect of disarming or resetting a timer on pending expiration notifications is unspecified.If the flag TIMER_ABSTIME is not set in the argument flags,
timer_settime() behaves as if the time until next expiration
is set to be equal to the interval specified by the it_value
member of value. That is, the timer expires in it_value
nanoseconds from when the call is made. If the flagTIMER_ABSTIME is set in the argument flags, timer_settime()
behaves as if the time until next expiration is set to be equal to the difference between the absolute time specifiedby the it_value member of value and the current value of the
clock associated with timerid. That is, the timer expireswhen the clock reaches the value specified by the it_value
member of value. If the specified time has already passed, the function succeeds and the expiration notification is made. The reload value of the timer is set to the value specifiedby the it_interval member of value. When a timer is armed
with a non-zero it_interval, a periodic (or repetitive)
timer is specified.SunOS 5.11 Last change: 5 Feb 2008 1
Standard C Library Functions timer_settime(3C)
Time values that are between two consecutive non-negative
integer multiples of the resolution of the specified timer will be rounded up to the larger multiple of the resolution.Quantization error will not cause the timer to expire ear-
lier than the rounded time value. If the argument ovalue is not NULL, the functiontimer_settime() stores, in the location referenced by
ovalue, a value representing the previous amount of time before the timer would have expired or 0 if the timer was disarmed, together with the previous timer reload value. The members of ovalue are subject to the resolution of the timer, and they are the same values that would be returnedby a timer_gettime() call at that point in time.
The timer_gettime() function stores the amount of time until
the specified timer, timerid, expires and the reload valueof the timer into the space pointed to by the value argu-
ment. The it_value member of this structure contains the
amount of time before the timer expires, or 0 if the timer is disarmed. This value is returned as the interval until timer expiration, even if the timer was armed with absolutetime. The it_interval member of value contains the reload
value last set by timer_settime().
Only a single signal will be queued to the process for a given timer at any point in time. When a timer for which a signal is still pending expires, no signal will be queued, and a timer overrun occurs. When a timer expiration signal is delivered to or accepted by a process, thetimer_getoverrun() function returns the timer expiration
overrun count for the specified timer. The overrun count returned contains the number of extra timer expirations that occurred between the time the signal was generated (queued)and when it was delivered or accepted, up to but not includ-
ing an implementation-dependent maximum of DELAYTIMER_MAX.
If the number of such extra expirations is greater than orequal to DELAYTIMER_MAX, then the overrun count will be set
to DELAYTIMER_MAX. The value returned by timer_getoverrun()
applies to the most recent expiration signal delivery or acceptance for the timer. If no expiration signal has been delivered for the timer, the meaning of the overrun count returned is undefined.RETURN VALUES
If the timer_settime() or timer_gettime() functions succeed,
0 is returned. If an error occurs for either of these func-
tions, -1 is returned, and errno is set to indicate the
error. If the timer_getoverrun() function succeeds, it
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Standard C Library Functions timer_settime(3C)
returns the timer expiration overrun count as explained above.ERRORS
The timer_settime(), timer_gettime() and timer_getoverrun()
functions will fail if: EINVAL The timerid argument does not correspond to atimer returned by timer_create(3C) but not yet
deleted by timer_delete(3C).
ENOSYS The timer_settime(), timer_gettime(), and
timer_getoverrun() functions are not supported by
the system. The timer_settime() function will
fail if: EINVAL A value structure specified a nanosecond value less than zero or greater than or equal to 1000 million.ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Interface Stability | Committed ||_____________________________|_____________________________|
| MT-Level | Async-Signal-Safe |
|_____________________________|_____________________________|
| Standard | See standards(5). ||_____________________________|_____________________________|
SEE ALSO
time.h(3HEAD), clock_settime(3C), timer_create(3C),
timer_delete(3C), attributes(5), standards(5)
SunOS 5.11 Last change: 5 Feb 2008 3