調用mpfr的一段示例（極不完整）

  char buffer[2048];
  mp_exp_t  e;
  unsigned int i;
  mpfr_t s, t, u;

  mpfr_init2 (t, 200);
  mpfr_set_d (t, 1.0, GMP_RNDD);
  mpfr_init2 (s, 200);
  mpfr_set_d (s, 1.0, GMP_RNDD);
  mpfr_init2 (u, 200);
  for (i = 1; i <= 100; i++)
    {
      mpfr_mul_ui (t, t, i, GMP_RNDU);
      mpfr_set_d (u, 1.0, GMP_RNDD);
      mpfr_div (u, u, t, GMP_RNDD);
      mpfr_add (s, s, u, GMP_RNDD);
    }
  //printf ("Sum is ");
  //mpfr_out_str (stdout, 10, 0, s, GMP_RNDD);
  //putchar ('\n');
  mpfr_sprintf(buffer, "%.9R", s);
  Memo1->Text = mpfr_get_str(NULL,&e,10,0, s, GMP_RNDD);
  mpfr_clear (s);
  mpfr_clear (t);
  mpfr_clear (u);