86400

The delay used in the main loop. It looks like some implementations
cannot handle the biggest integer value, as it has been calculated:

   /* calculate biggest value */
   ts.tv_sec = -1;
   if(ts.tv_sec < 0) {
      ts.tv_sec = 1 << ((sizeof(ts.tv_sec) * 8)-1);
      ts.tv_sec = ts.tv_sec - 1;
   }