timer_getoverrun(3) Library Functions Manual timer_getoverrun(3)NAME
timer_getoverrun - Obtains the overrun count for a specified timer
LIBRARY
Realtime Library (librt.so, librt.a)
SYNOPSIS
include <time.h>
int timer_getoverrun ( timer_t timerid );
PARAMETERS
timerid The timer for which to return the overrun count.
DESCRIPTION
The timer_getoverrun function returns the overrun count for a specified timer. The count contains the number of extra timer expirations
that occurred between the time the signal was queued and when it was delivered, up to but not including the implementation-defined maximum
DELAYTIMER_MAX.
RETURN VALUES
Upon successful completion, the timer_getoverrun function returns the overrun count for the timer specified. If the timer overrun count is
equal to or greater than DELAYTIMER_MAX, the overrun count is set to DELAYTIMER_MAX. If the function fails, it returns -1 and sets errno
to indicate the type of error that occurred.
ERRORS
The timer_getoverrun function fails under the following condition:
[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)
Guide to Realtime Programming delim off
timer_getoverrun(3)
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timer_settime(3RT) Realtime Library Functions timer_settime(3RT)NAME
timer_settime, timer_gettime, timer_getoverrun - per-process timers
SYNOPSIS
cc [ flag... ] file... -lrt [ library... ]
#include <time.h>
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 the it_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 value specified. If the it_value member of value is 0, the timer is dis-
armed. 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 flag TIMER_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 specified by the it_value member of value and the current value of the clock associated with
timerid. That is, the timer expires when 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 specified by the it_interval member of value. When a timer is armed with a non-zero
it_interval, a periodic (or repetitive) timer is specified.
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 earlier than the rounded time value.
If the argument ovalue is not NULL, the function timer_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 returned by 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 value of the timer into
the space pointed to by the value argument. 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 absolute time.
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, the
timer_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 including an implementation-dependent maximum of DELAYTIMER_MAX. If the number of such extra expirations is greater than or
equal 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 functions, -1 is
returned, and errno is set to indicate the error. If the timer_getoverrun() function succeeds, it 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 a timer returned by timer_create(3RT) but not yet deleted by timer_delete(3RT).
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 attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
|MT-Level |Async-Signal-Safe |
+-----------------------------+-----------------------------+
SEE ALSO time.h(3HEAD), clock_settime(3RT), timer_create(3RT), timer_delete(3RT), attributes(5), standards(5)SunOS 5.10 1 Nov 2003 timer_settime(3RT)