invalid use of imcomplete struct_tms given error and also error is forward declaration
static double cycles_diff(struct tms *a,struct tms *b)

{

   
        clock_t aa = a->tms_utime  +
                   a->tms_stime  +
                   a->tms_cutime +
                   a->tms_cstime;

      clock_t bb = b->tms_utime
            +      b->tms_stime
            +      b->tms_cutime
            +      b->tms_cstime;

      return (aa-bb)/(double)sysconf(_SC_CLK_TCK);
  }
invalid use of imcomplete struct_tms given error and also error is forward declaration
===

static double cycles_diff(struct tms *a,struct tms *b)

{

   
        clock_t aa = a->tms_utime  +
                   a->tms_stime  +
                   a->tms_cutime +
                   a->tms_cstime;

      clock_t bb = b->tms_utime
            +      b->tms_stime
            +      b->tms_cutime
            +      b->tms_cstime;

      return (aa-bb)/(double)sysconf(_SC_CLK_TCK);
  }