#include <stdio.h>
#include <unistd.h>
#include <sys/io.h>

int main( void )
{
  int value;

  if ( ioperm( 0x70, 2, 1 ) )
  {
    perror( "Error" );
    fprintf( stderr, "You must be root to run this program.\n" );

    return 1;
  }

  fprintf( stderr, "Restarting RTC clock...\n" );

  outb( 0xb, 0x70 );
  value = inb( 0x71 );

  value |= 0x80;

  outb( 0xb, 0x70 );
  outb( value, 0x71 );

  sleep( 2 );

  value &= 0x7f;

  outb( 0xb, 0x70 );
  outb( value, 0x71 );

  return 0;
}