Get the value of an interval timer
#include <sys/time.h> int getitimer ( int which, struct itimerval *value );
- The interval time whose value you want to get. Currently, this must be ITIMER_REAL.
- A pointer to a itimerval structure where the function can store the value of the interval timer.
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.
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 struct timeval contains the following members:
- time_t tv_sec — the number of seconds since the start of the Unix Epoch.
- 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:
- Decrements in real time. A SIGALRM signal is delivered when this timer expires.
- An error occurred (errno is set).
- 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.