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.

Description:

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.

A timer value is defined by the itimerval structure (see gettimeofday() for the definition of timeval), which includes the following members:

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

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 specified number of seconds is greater than 100,000,000, the number of microseconds is greater than or equal to 1,000,000, or the which argument is unrecognized.

Classification:

POSIX 1003.1 XSI

See also:

alarm(), gettimeofday(), pthread_attr_setscope(), pthread_sigmask(), setitimer(), sigprocmask(), sleep(), sysconf()

Tick, Tock: Understanding the Neutrino Microkernel's Concept of Time chapter of the QNX Neutrino Programmer's Guide