Function tostringbuffFloat

src/lobject.cpp:459–475

** Convert a float to a string, adding it to a buffer. First try with ** a not too large number of digits, to avoid noise (for instance, ** 1.1 going to "1.1000000000000001"). If that lose precision, so ** that reading the result back gives a different number, then do the ** conversion again with extra precision. Moreover, if the numeral looks ** like an integer (without a decimal point or an expo

** its end.
*/
static int tostringbuffFloat (lua_Number n, char *buff) {
  /* first conversion */
  int len = l_sprintf(buff, LUA_N2SBUFFSZ, LUA_NUMBER_FMT,
                            (LUAI_UACNUMBER)n);
  lua_Number check = lua_str2number(buff, NULL);  /* read it back */
  if (check != n) {  /* not enough precision? */
    /* convert again with more precision */
    len = l_sprintf(buff, LUA_N2SBUFFSZ, LUA_NUMBER_FMT_N,
                          (LUAI_UACNUMBER)n);
  }
  /* looks like an integer? */
  if (buff[strspn(buff, "-0123456789")] == '\0') {
    buff[len++] = lua_getlocaledecpoint();
    buff[len++] = '0';  /* adds '.0' to result */
  }
  return len;
}


/*