#include <string.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <signal.h>
#include <stdio.h>
#include <unistd.h>

struct timeval getTV;
struct timezone getTZ;
double prevValue=0.0, curValue=0.0;


void sigHand( int i ){
    gettimeofday( &getTV, &getTZ );
    prevValue = curValue;
    curValue = getTV.tv_sec+(double)getTV.tv_usec/1.0e6;
}

int main( int argc, char ** argv ) {

    ::setpriority( PRIO_PROCESS, 0, -19 );
    struct sigaction sa;
    memset( &sa, 0, sizeof(sa) );
    sa.sa_handler = sigHand;
    sigaction( SIGALRM, &sa, NULL );

    struct itimerval tv;
    tv.it_interval.tv_sec = 0;
    tv.it_interval.tv_usec = 30000;
    tv.it_value.tv_sec = 0;
    tv.it_value.tv_usec = 30000;
    setitimer( ITIMER_REAL, &tv, NULL );

    while( 1 ) {
        pause();
//	printf("%10.3f\n",curValue);
	printf("Cur=%16.6fs, Prev=%16.6fs, delta=%8.3fms\n",curValue,prevValue,(curValue-prevValue)*1.0e3);
    }
}