/*-------------------------------------------------------------------*/
/* testitimersigaction.c                                             */
/* The setitimer and sigaction system calls.                         */
/*-------------------------------------------------------------------*/

#define _GNU_SOURCE

#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <ucontext.h>
#include <sys/time.h>

/*-------------------------------------------------------------------*/

static void mySigAction(int iSignal, siginfo_t *psSigInfo, void *pvContext)

/* This function is intended to be a handler for signals of type 
   SIGPROF.  Print to stdout the value of the EIP register at the time 
   the signal occurred. */

{
   ucontext_t *psContext = (ucontext_t*)pvContext;
   int iEip;

   /* Print the contents of the eip register at the time the
      signal occurred. */
   iEip = psContext->uc_mcontext.gregs[REG_EIP];
   printf("%x\n", iEip);
}

/*-------------------------------------------------------------------*/

int main(int argc, char *argv[])

/* Illustrate the setitimer and sigaction system calls. */

{
   struct sigaction sSigAction;
   struct sigaction sOldSigAction;   

   struct itimerval sTimerValue;
   struct itimerval sOldTimerValue;

   /* Register a signal handler to handle SIGPROF signals. */
   sSigAction.sa_flags = SA_SIGINFO;
   sSigAction.sa_sigaction = mySigAction;
   sigemptyset(&sSigAction.sa_mask);
   sigaction(SIGPROF, &sSigAction, &sOldSigAction);

   /* Create an interval timer to generate a SIGPROF signal after 
      A seconds and B microseconds of virtual time.  Thereafter 
      repeatedly generate a SIGPROF signal at C second, D microsecond
      intervals of virtual time. */
   sTimerValue.it_value.tv_sec = 1;      /* A */
   sTimerValue.it_value.tv_usec = 0;     /* B */
   sTimerValue.it_interval.tv_sec = 1;   /* C */
   sTimerValue.it_interval.tv_usec = 0;  /* D */
   setitimer(ITIMER_PROF, &sTimerValue, &sOldTimerValue);

   /* Do some nonsensical computation, forever. */
   {
      int i;
      i = 1;
      for (;;)
      {
         i += 1;
         i += i * i;
      }
   }
}


/* Sample execution:

$ gcc -Wall -ansi -pedantic -o testitimersigaction testitimersigaction.c
$ testitimersigaction
804850a
80484f3
80484f3
8048502
80484eb
80484fb
80484f1
80484fb
8048502
8048502
804850a
8048502
8048502
8048502
80484fb
^C

*/