getitimer()

Get the value of an interval timer

Synopsis:

#include <sys/time.h>

int getitimer ( int which,
                struct itimerval *value );

Arguments:

which: The interval time whose value you want to get. Currently, this must be ITIMER_REAL.
value: A pointer to a itimerval structure where the function can store the value of the interval timer.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

The system provides each process with several interval timers, defined in <sys/time.h>. The getitimer() function stores the current value of the timer specified by which into the structure pointed to by value.

You should use timer_gettime() and timer_settime() instead of the obsolescent getitimer() and setitimer().

A timer value is defined by the itimerval structure, which includes the following members:

struct timeval    it_interval;    /* timer interval */
struct timeval    it_value;       /* current value */

Each timeval structure contains the following members:

time_t tv_sec — the number of seconds.
suseconds_t tv_usec — the number of microseconds.

The it_value member indicates the time to the next timer expiration. The it_interval member specifies a value to be used in reloading it_value when the timer expires. Setting it_value to 0 disables a timer, regardless of the value of it_interval. Setting it_interval to 0 disables a timer after its next expiration (assuming it_value is nonzero).

Time values smaller than the resolution of the system clock are rounded up to the resolution of the system clock.

The interval timers include:

ITIMER_REAL: Decrements in real time. A SIGALRM signal is delivered when this timer expires.

Returns:

0: Success.
-1: An error occurred (errno is set).

Errors:

EINVAL: The which argument is unrecognized.

Classification:

POSIX 1003.1 XSI (but obsolescent)

Safety:
Cancellation point	No
Interrupt handler	No
Signal handler	Yes
Thread	Yes