CODEWITHSUNDEEP
ctimersystem-calls
Richard
Richard

Reputation: 15562

Virtual time expired

I have the following code, which throws the error

Virtual time expired.

Shouldn't the program run in an infinite loop?

#define KTHREAD_VTALRM_SEC 0
#define KTHREAD_VTALRM_USEC 100000
#include <stdio.h>
#include <unistd.h>
#include <linux/unistd.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sched.h>
#include <signal.h>
#include <setjmp.h>
#include <errno.h>
#include <assert.h>
#include <string.h>

#include <time.h>
int main()

{
    struct itimerval timeslice;

    timeslice.it_interval.tv_sec = KTHREAD_VTALRM_SEC;
    timeslice.it_interval.tv_usec = KTHREAD_VTALRM_USEC;
    timeslice.it_value.tv_sec = KTHREAD_VTALRM_SEC;
    timeslice.it_value.tv_usec = KTHREAD_VTALRM_USEC;

    setitimer(ITIMER_VIRTUAL,&timeslice,NULL);

    while(1)
    {
        ;
    }
}

Upvotes: 0

Views: 1857

Answers (3)

par
par

Reputation: 17724

When the timer expires it will deliver a SIGVTALRM signal, which you are not handling.

See the man pages for setitimer() and signal().

Upvotes: 2

vad
vad

Reputation: 344

The default handler for VTALRM signal is "exit" (ref: http://manpages.ubuntu.com/manpages//precise/en/man1/kill.1.html.)
So if you want to replace the default behavior with yours, you have to define a new signal handler and register it:

void vtHandler(int sig)
{
  // Do something here
}

int main()
{
    // Register timer handler
    struct sigaction sa;
    sigemptyset(&sa.sa_mask);
    sa.sa_flags = 0;
    sa.sa_handler = timer_handler;

    if (sigaction(SIGVTALRM, &sa, NULL) == -1)
        //error handle
        ;
}

PS: If you utilize signal method, sure that it is well implemented on your system (ref: http://manpages.ubuntu.com/manpages//precise/en/man2/signal.2.html)

Upvotes: 0

Zan Lynx
Zan Lynx

Reputation: 54335

You did not set a signal handler.

Upvotes: 0

Related Questions