TimerInfo(), TimerInfo_r()

Get information about a timer


#include <sys/neutrino.h>

int TimerInfo( pid_t pid,
               timer_t id,
               int flags,
               struct _timer_info* info );

int TimerInfo_r( pid_t pid,
                 timer_t id,
                 int flags,
                 struct _timer_info* info );


The process ID that you're requesting the timer information for.
The ID of the timer, as returned by TimerCreate().
Supported flags are:
  • _NTO_TIMER_SEARCH — if this flag is specified and the timer ID doesn't exist, return information on the next timer ID. This provides a mechanism to discover all of the timers in the process.
  • _NTO_TIMER_RESET_OVERRUNS — reset the timer's overrun count to zero.
  • _NTO_TI_REPORT_TOLERANCE — store the timer tolerance in the otime.interval_nsec member of the _timer_info structure.
A pointer to a _timer_info structure where the function can store the information about the specified timer. For more details, see "struct _timer_info," below.

You can pass NULL for this argument if the only bit set in flags is _NTO_TIMER_RESET_OVERRUNS.



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


These kernel calls get information about a previously created timer specified by id, and store the information in the buffer pointed to by info.

The TimerInfo() and TimerInfo_r() functions are identical except in the way they indicate errors. See the Returns section for details.

  • Instead of using these kernel calls directly, consider calling timer_getexpstatus(), timer_getoverrun(), or timer_gettime().
  • In order to get timer information about a process belonging to a different user and simultaneously use the _NTO_TIMER_RESET_OVERRUNS flag, your process must have the PROCMGR_AID_TIMER ability enabled. For more information, see procmgr_ability().
  • There's no generic way to query when a timer was activated. However, you can determine the activation time by reading the timer information after activation (TimerSettime() activates the timer) but before the first time the timer is fired, and then subtract the known initial interval (that is, for TimerSettime(), the value of struct _itimer nsec).

struct _timer_info

The _timer_info structure pointed to by info contains at least these members:

uint32_t flags
One or more of these bit flags:
The timer is waiting for an absolute time to occur; otherwise, the timer is relative.
The timer is active.
The timer has expired.
The timer is precise, and excludes any default tolerance that was set for the process (see procmgr_timer_tolerance()).
The timer is using the process's default tolerance.
The timer targets the process, not a specific thread.
The timer the timer is based relative to the beginning of the Epoch (January 1, 1970, 00:00:00 GMT); otherwise, it's relative to the time that QNX Neutrino was started on the machine (see the system page qtime boot_time member).
The timer has a nonzero tolerance (which could be the process's default tolerance).
int32_t tid
The thread to which the timer is directed (0 if it's directed to the process).
int32_t notify
The bottom 16 bits are the value of sigev_notify for the associated sigevent. The other bits are used internally.
clockid_t clockid
The type of clock used.
uint32_t overruns
The number of overruns.
struct sigevent event
The event dispatched when the timer expires.
struct _itimer itime
A struct _itimer with the following fields:
uint64_t nsec
When the timer is next scheduled to fire.
uint64_t interval_nsec
The timer's interval.
struct _itimer otime
The time remaining before the timer expires. If you specified _NTO_TI_REPORT_TOLERANCE in the flags argument, otime.interval_nsec is set to the timer tolerance.

For more information, see the description of TimerCreate().

Blocking states

These calls don't block.


The ID of the timer that the information is for. If an error occurs:


The timer specified by id doesn't exist.
The calling process doesn't have the required permission; see procmgr_ability().
The process specified by pid doesn't exist.


QNX Neutrino

Cancellation point No
Interrupt handler No
Signal handler Yes
Thread Yes