| Updated: October 28, 2024 |
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 );
You can pass NULL for this argument if the only bit set in flags is _NTO_TIMER_RESET_OVERRUNS.
libc
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.
struct _timer_info
The _timer_info structure pointed to by info contains at least these members:
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:
This program creates a timer and then gets information about it. The arguments are the timer's tolerance, the process's default tolerance, and a flag that indicates whether or not to use the process's default tolerance. For more information, see “Tolerant and high-resolution timers” in the “Understanding the Microkernel's Concept of Time” chapter of the QNX Neutrino Programmer's Guide.
#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/neutrino.h>
#include <sys/procmgr.h>
int main (int argc, char **argv)
{
struct sigevent event;
timer_t timerId;
int tolerance = 0;
struct itimerspec newTimerTolerance, newTimerSpec;
int rc;
struct _timer_info tinfo;
struct _clockperiod period;
int precise = 0, not_used = 0;
uint64_t p_tolerance = 0;
if (argc > 1) {
tolerance = atoi (argv[1]);
}
if (argc > 2) {
p_tolerance = atoi (argv[2]);
}
if (argc > 3) {
precise = atoi (argv[3]);
}
// Set the process's default tolerance if it's nonzero.
if (p_tolerance != 0) {
rc = procmgr_timer_tolerance ( 0, &p_tolerance, NULL);
if (rc == -1)
{
perror ("procmgr_timer_tolerance");
return EXIT_FAILURE;
}
}
event.sigev_notify = SIGEV_SIGNAL;
event.sigev_signo = SIGUSR1;
// Create a timer.
rc = timer_create(CLOCK_MONOTONIC, &event, &timerId);
if (rc == -1)
{
perror ("timer_create()");
return EXIT_FAILURE;
}
// Set the tolerance on the timer first because
// setting the time activates the timer.
memset(&newTimerTolerance, 0, sizeof(newTimerTolerance));
newTimerTolerance.it_value.tv_sec = 0;
newTimerTolerance.it_value.tv_nsec = tolerance;
newTimerTolerance.it_interval.tv_sec = 0;
newTimerTolerance.it_interval.tv_nsec = 0;
rc = timer_settime(timerId, TIMER_TOLERANCE, &newTimerTolerance, NULL);
if (rc == -1)
{
perror ("timer_settime() tolerance");
return EXIT_FAILURE;
}
memset(&newTimerSpec, 0, sizeof(newTimerSpec));
newTimerSpec.it_value.tv_sec = 5;
newTimerSpec.it_value.tv_nsec = 5000;
newTimerSpec.it_interval.tv_sec = 0;
newTimerSpec.it_interval.tv_nsec = 0;
rc = timer_settime(timerId, precise ? TIMER_PRECISE : 0, &newTimerSpec, NULL);
if (rc == -1)
{
perror ("timer_settime() time");
return EXIT_FAILURE;
}
// Get the clock period.
rc = ClockPeriod (CLOCK_MONOTONIC, NULL, &period, not_used);
if (rc == -1)
{
perror ("ClockPeriod()");
return EXIT_FAILURE;
}
printf ("Clock period: %d ns\n\n", period.nsec);
// Get information about the timer.
memset(&tinfo, 0, sizeof(struct _timer_info));
rc = TimerInfo ( getpid(), timerId, _NTO_TI_REPORT_TOLERANCE, &tinfo);
if (rc == -1)
{
perror ("TimerInfo()");
return EXIT_FAILURE;
}
printf ("Timer information:\n");
printf (" Thread ID: %d\n", tinfo.tid);
switch (tinfo.clockid) {
case CLOCK_MONOTONIC:
printf (" CLOCK_MONOTONIC\n");
break;
case CLOCK_REALTIME:
printf (" CLOCK_REALTIME\n");
break;
case CLOCK_SOFTTIME:
printf (" CLOCK_SOFTTIME\n");
break;
}
printf (" Overruns: %d\n", tinfo.overruns);
printf (" Start time: %ld ns; interval: %ld ns\n", tinfo.itime.nsec,
tinfo.itime.interval_nsec);
printf (" Remaining : %ld ns\n", tinfo.otime.nsec);
if (tinfo.flags &_NTO_TI_ABSOLUTE) {
printf (" ABSOLUTE\n");
} else {
printf (" Relative\n");
}
if (tinfo.flags &_NTO_TI_ACTIVE) {
printf (" ACTIVE\n");
}
if (tinfo.flags &_NTO_TI_EXPIRED) {
printf (" EXPIRED\n");
}
if (tinfo.flags &_NTO_TI_PRECISE) {
printf (" PRECISE\n");
}
if (tinfo.flags &_NTO_TI_PROCESS_TOLERANT) {
printf (" PROCESS_TOLERANT: %ld ns.\n", p_tolerance);
}
if (tinfo.flags &_NTO_TI_TARGET_PROCESS) {
printf (" TARGET_PROCESS\n");
}
if (tinfo.flags &_NTO_TI_TOD_BASED) {
printf (" TOD_BASED\n");
}
if (tinfo.flags &_NTO_TI_TOLERANT) {
printf (" TOLERANT");
tolerance = tinfo.otime.interval_nsec;
if ((tolerance > 0) && (tolerance < period.nsec)) {
printf (" (high-resolution): %d ns.\n", tolerance);
} else {
printf (": %d ns.\n", tolerance);
}
}
return EXIT_SUCCESS;
}
| Safety: | |
|---|---|
| Cancellation point | No |
| Interrupt handler | No |
| Signal handler | Yes |
| Thread | Yes |