class IO

Public Class Methods

console → #<File:/dev/tty> click to toggle source

console(sym, *args)

Returns an File instance opened console.

If sym is given, it will be sent to the opened console with args and the result will be returned instead of the console IO itself.

You must require ‘io/console’ to use this method.

static VALUE
console_dev(int argc, VALUE *argv, VALUE klass)
{
    VALUE con = 0;
    VALUE sym = 0;

    rb_check_arity(argc, 0, UNLIMITED_ARGUMENTS);

    if (argc) {
        Check_Type(sym = argv[0], T_SYMBOL);
    }

    // Force the class to be File.
    if (klass == rb_cIO) klass = rb_cFile;

    if (console_dev_get(klass, &con)) {
        if (!RB_TYPE_P(con, T_FILE) || RTEST(rb_io_closed_p(con))) {
            console_dev_remove(klass);
            con = 0;
        }
    }

    if (sym) {
        if (sym == ID2SYM(id_close) && argc == 1) {
            if (con) {
                rb_io_close(con);
                console_dev_remove(klass);
                con = 0;
            }
            return Qnil;
        }
    }

    if (!con) {
#if defined HAVE_TERMIOS_H || defined HAVE_TERMIO_H || defined HAVE_SGTTY_H
# define CONSOLE_DEVICE "/dev/tty"
#elif defined _WIN32
# define CONSOLE_DEVICE "con$"
# define CONSOLE_DEVICE_FOR_READING "conin$"
# define CONSOLE_DEVICE_FOR_WRITING "conout$"
#endif
#ifndef CONSOLE_DEVICE_FOR_READING
# define CONSOLE_DEVICE_FOR_READING CONSOLE_DEVICE
#endif
#ifdef CONSOLE_DEVICE_FOR_WRITING
        VALUE out;
#endif
        int fd;
        VALUE path = rb_obj_freeze(rb_str_new2(CONSOLE_DEVICE));

#ifdef CONSOLE_DEVICE_FOR_WRITING
        fd = rb_cloexec_open(CONSOLE_DEVICE_FOR_WRITING, O_RDWR, 0);
        if (fd < 0) return Qnil;
        out = rb_io_open_descriptor(klass, fd, FMODE_WRITABLE | FMODE_SYNC, path, Qnil, NULL);
#endif
        fd = rb_cloexec_open(CONSOLE_DEVICE_FOR_READING, O_RDWR, 0);
        if (fd < 0) {
#ifdef CONSOLE_DEVICE_FOR_WRITING
            rb_io_close(out);
#endif
            return Qnil;
        }

        con = rb_io_open_descriptor(klass, fd, FMODE_READWRITE | FMODE_SYNC, path, Qnil, NULL);
#ifdef CONSOLE_DEVICE_FOR_WRITING
        rb_io_set_write_io(con, out);
#endif
        console_dev_set(klass, con);
    }

    if (sym) {
        return rb_f_send(argc, argv, con);
    }

    return con;
}

console_size()

Alias for: default_console_size

default_console_size() click to toggle source

fallback to console window size

# File io/console/lib/console/size.rb, line 3
def IO.default_console_size
  [
    ENV["LINES"].to_i.nonzero? || 25,
    ENV["COLUMNS"].to_i.nonzero? || 80,
  ]
end

Also aliased as: console_size

Public Instance Methods

beep click to toggle source

Beeps on the output console.

You must require ‘io/console’ to use this method.

static VALUE
console_beep(VALUE io)
{
#ifdef _WIN32
    MessageBeep(0);
#else
    int fd = GetWriteFD(io);
    if (write(fd, "\a", 1) < 0) sys_fail(io);
#endif
    return io;
}

check_winsize_changed { ... } → io click to toggle source

Yields while console input events are queued.

This method is Windows only.

You must require ‘io/console’ to use this method.

static VALUE
console_check_winsize_changed(VALUE io)
{
    HANDLE h;
    DWORD num;

    h = (HANDLE)rb_w32_get_osfhandle(GetReadFD(io));
    while (GetNumberOfConsoleInputEvents(h, &num) && num > 0) {
        INPUT_RECORD rec;
        if (ReadConsoleInput(h, &rec, 1, &num)) {
            if (rec.EventType == WINDOW_BUFFER_SIZE_EVENT) {
                rb_yield(Qnil);
            }
        }
    }
    return io;
}

clear_screen → io click to toggle source

Clears the entire screen and moves the cursor top-left corner.

You must require ‘io/console’ to use this method.

static VALUE
console_clear_screen(VALUE io)
{
    console_erase_screen(io, INT2FIX(2));
    console_goto(io, INT2FIX(0), INT2FIX(0));
    return io;
}

console_mode → mode click to toggle source

Returns a data represents the current console mode.

You must require ‘io/console’ to use this method.

static VALUE
console_conmode_get(VALUE io)
{
    conmode t;
    int fd = GetReadFD(io);

    if (!getattr(fd, &t)) sys_fail(io);

    return conmode_new(cConmode, &t);
}

console_mode = mode click to toggle source

Sets the console mode to mode.

You must require ‘io/console’ to use this method.

static VALUE
console_conmode_set(VALUE io, VALUE mode)
{
    conmode *t, r;
    int fd = GetReadFD(io);

    TypedData_Get_Struct(mode, conmode, &conmode_type, t);
    r = *t;

    if (!setattr(fd, &r)) sys_fail(io);

    return mode;
}

cooked {|io| } click to toggle source

Yields self within cooked mode.

STDIN.cooked(&:gets)

will read and return a line with echo back and line editing.

You must require ‘io/console’ to use this method.

static VALUE
console_cooked(VALUE io)
{
    return ttymode(io, rb_yield, io, set_cookedmode, NULL);
}

cooked! click to toggle source

Enables cooked mode.

If the terminal mode needs to be back, use io.cooked { … }.

You must require ‘io/console’ to use this method.

static VALUE
console_set_cooked(VALUE io)
{
    conmode t;
    int fd = GetReadFD(io);
    if (!getattr(fd, &t)) sys_fail(io);
    set_cookedmode(&t, NULL);
    if (!setattr(fd, &t)) sys_fail(io);
    return io;
}

cursor → [row, column] click to toggle source

Returns the current cursor position as a two-element array of integers (row, column)

io.cursor # => [3, 5]

You must require ‘io/console’ to use this method.

static VALUE
console_cursor_pos(VALUE io)
{
#ifdef _WIN32
    rb_console_size_t ws;
    int fd = GetWriteFD(io);
    if (!GetConsoleScreenBufferInfo((HANDLE)rb_w32_get_osfhandle(fd), &ws)) {
        rb_syserr_fail(LAST_ERROR, 0);
    }
    return rb_assoc_new(UINT2NUM(ws.dwCursorPosition.Y), UINT2NUM(ws.dwCursorPosition.X));
#else
    static const struct query_args query = {"\033[6n", 0};
    VALUE resp = console_vt_response(0, 0, io, &query);
    VALUE row, column, term;
    unsigned int r, c;
    if (!RB_TYPE_P(resp, T_ARRAY) || RARRAY_LEN(resp) != 3) return Qnil;
    term = RARRAY_AREF(resp, 2);
    if (!RB_TYPE_P(term, T_STRING) || RSTRING_LEN(term) != 1) return Qnil;
    if (RSTRING_PTR(term)[0] != 'R') return Qnil;
    row = RARRAY_AREF(resp, 0);
    column = RARRAY_AREF(resp, 1);
    rb_ary_resize(resp, 2);
    r = NUM2UINT(row) - 1;
    c = NUM2UINT(column) - 1;
    RARRAY_ASET(resp, 0, INT2NUM(r));
    RARRAY_ASET(resp, 1, INT2NUM(c));
    return resp;
#endif
}

cursor = [line, column] → io click to toggle source

Same as io.goto(line, column)

See IO#goto.

You must require ‘io/console’ to use this method.

static VALUE
console_cursor_set(VALUE io, VALUE cpos)
{
    cpos = rb_convert_type(cpos, T_ARRAY, "Array", "to_ary");
    if (RARRAY_LEN(cpos) != 2) rb_raise(rb_eArgError, "expected 2D coordinate");
    return console_goto(io, RARRAY_AREF(cpos, 0), RARRAY_AREF(cpos, 1));
}

cursor_down(n) → io click to toggle source

Moves the cursor down n lines.

You must require ‘io/console’ to use this method.

static VALUE
console_cursor_down(VALUE io, VALUE val)
{
    return console_move(io, +NUM2INT(val), 0);
}

cursor_left(n) → io click to toggle source

Moves the cursor left n columns.

You must require ‘io/console’ to use this method.

static VALUE
console_cursor_left(VALUE io, VALUE val)
{
    return console_move(io, 0, -NUM2INT(val));
}

cursor_right(n) → io click to toggle source

Moves the cursor right n columns.

You must require ‘io/console’ to use this method.

static VALUE
console_cursor_right(VALUE io, VALUE val)
{
    return console_move(io, 0, +NUM2INT(val));
}

cursor_up(n) → io click to toggle source

Moves the cursor up n lines.

You must require ‘io/console’ to use this method.

static VALUE
console_cursor_up(VALUE io, VALUE val)
{
    return console_move(io, -NUM2INT(val), 0);
}

echo = flag click to toggle source

Enables/disables echo back. On some platforms, all combinations of this flags and raw/cooked mode may not be valid.

You must require ‘io/console’ to use this method.

static VALUE
console_set_echo(VALUE io, VALUE f)
{
    conmode t;
    int fd = GetReadFD(io);

    if (!getattr(fd, &t)) sys_fail(io);

    if (RTEST(f))
        set_echo(&t, NULL);
    else
        set_noecho(&t, NULL);

    if (!setattr(fd, &t)) sys_fail(io);

    return io;
}

echo? → true or false click to toggle source

Returns true if echo back is enabled.

You must require ‘io/console’ to use this method.

static VALUE
console_echo_p(VALUE io)
{
    conmode t;
    int fd = GetReadFD(io);

    if (!getattr(fd, &t)) sys_fail(io);
    return echo_p(&t) ? Qtrue : Qfalse;
}

erase_line(mode) → io click to toggle source

Erases the line at the cursor corresponding to mode. mode may be either: 0: after cursor 1: before and cursor 2: entire line

You must require ‘io/console’ to use this method.

static VALUE
console_erase_line(VALUE io, VALUE val)
{
    int mode = mode_in_range(val, 2, "line erase");
#ifdef _WIN32
    HANDLE h;
    rb_console_size_t ws;
    COORD *pos = &ws.dwCursorPosition;
    DWORD w;

    h = (HANDLE)rb_w32_get_osfhandle(GetWriteFD(io));
    if (!GetConsoleScreenBufferInfo(h, &ws)) {
        rb_syserr_fail(LAST_ERROR, 0);
    }
    w = winsize_col(&ws);
    switch (mode) {
      case 0:                   /* after cursor */
        w -= pos->X;
        break;
      case 1:                   /* before *and* cursor */
        w = pos->X + 1;
        pos->X = 0;
        break;
      case 2:                   /* entire line */
        pos->X = 0;
        break;
    }
    constat_clear(h, ws.wAttributes, w, *pos);
    return io;
#else
    rb_io_write(io, rb_sprintf(CSI "%dK", mode));
#endif
    return io;
}

erase_screen(mode) → io click to toggle source

Erases the screen at the cursor corresponding to mode. mode may be either: 0: after cursor 1: before and cursor 2: entire screen

You must require ‘io/console’ to use this method.

static VALUE
console_erase_screen(VALUE io, VALUE val)
{
    int mode = mode_in_range(val, 3, "screen erase");
#ifdef _WIN32
    HANDLE h;
    rb_console_size_t ws;
    COORD *pos = &ws.dwCursorPosition;
    DWORD w;

    h = (HANDLE)rb_w32_get_osfhandle(GetWriteFD(io));
    if (!GetConsoleScreenBufferInfo(h, &ws)) {
        rb_syserr_fail(LAST_ERROR, 0);
    }
    w = winsize_col(&ws);
    switch (mode) {
      case 0:   /* erase after cursor */
        w = (w * (ws.srWindow.Bottom - pos->Y + 1) - pos->X);
        break;
      case 1:   /* erase before *and* cursor */
        w = (w * (pos->Y - ws.srWindow.Top) + pos->X + 1);
        pos->X = 0;
        pos->Y = ws.srWindow.Top;
        break;
      case 2:   /* erase entire screen */
        w = (w * winsize_row(&ws));
        pos->X = 0;
        pos->Y = ws.srWindow.Top;
        break;
      case 3:   /* erase entire screen */
        w = (w * ws.dwSize.Y);
        pos->X = 0;
        pos->Y = 0;
        break;
    }
    constat_clear(h, ws.wAttributes, w, *pos);
#else
    rb_io_write(io, rb_sprintf(CSI "%dJ", mode));
#endif
    return io;
}

getch(min: nil, time: nil, intr: nil) → char click to toggle source

Reads and returns a character in raw mode.

See IO#raw for details on the parameters.

You must require ‘io/console’ to use this method.

static VALUE
console_getch(int argc, VALUE *argv, VALUE io)
{
    rawmode_arg_t opts, *optp = rawmode_opt(&argc, argv, 0, 0, &opts);
#ifndef _WIN32
    return ttymode(io, getc_call, io, set_rawmode, optp);
#else
    rb_io_t *fptr;
    VALUE str;
    wint_t c;
    int len;
    char buf[8];
    wint_t wbuf[2];
# ifndef HAVE_RB_IO_WAIT
    struct timeval *to = NULL, tv;
# else
    VALUE timeout = Qnil;
# endif

    GetOpenFile(io, fptr);
    if (optp) {
        if (optp->vtime) {
# ifndef HAVE_RB_IO_WAIT
            to = &tv;
# else
            struct timeval tv;
# endif
            tv.tv_sec = optp->vtime / 10;
            tv.tv_usec = (optp->vtime % 10) * 100000;
# ifdef HAVE_RB_IO_WAIT
            timeout = rb_fiber_scheduler_make_timeout(&tv);
# endif
        }
        switch (optp->vmin) {
          case 1: /* default */
            break;
          case 0: /* return nil when timed out */
            if (optp->vtime) break;
            /* fallthru */
          default:
            rb_warning("min option larger than 1 ignored");
        }
        if (optp->intr) {
# ifndef HAVE_RB_IO_WAIT
            int w = rb_wait_for_single_fd(fptr->fd, RB_WAITFD_IN, to);
            if (w < 0) rb_eof_error();
            if (!(w & RB_WAITFD_IN)) return Qnil;
# else
            VALUE result = rb_io_wait(io, RB_INT2NUM(RUBY_IO_READABLE), timeout);
            if (!RTEST(result)) return Qnil;
# endif
        }
        else if (optp->vtime) {
            rb_warning("Non-zero vtime option ignored if intr flag is unset");
        }
    }
    len = (int)(VALUE)rb_thread_call_without_gvl(nogvl_getch, wbuf, RUBY_UBF_IO, 0);
    switch (len) {
      case 0:
        return Qnil;
      case 2:
        buf[0] = (char)wbuf[0];
        c = wbuf[1];
        len = 1;
        do {
            buf[len++] = (unsigned char)c;
        } while ((c >>= CHAR_BIT) && len < (int)sizeof(buf));
        return rb_str_new(buf, len);
      default:
        c = wbuf[0];
        len = rb_uv_to_utf8(buf, c);
        str = rb_utf8_str_new(buf, len);
        return rb_str_conv_enc(str, NULL, rb_default_external_encoding());
    }
#endif
}

getpass(prompt=nil) → string click to toggle source

Reads and returns a line without echo back. Prints prompt unless it is nil.

The newline character that terminates the read line is removed from the returned string, see String#chomp!.

You must require ‘io/console’ to use this method.

require 'io/console'
IO::console.getpass("Enter password:")
Enter password:
# => "mypassword"

static VALUE
console_getpass(int argc, VALUE *argv, VALUE io)
{
    VALUE str, wio;

    rb_check_arity(argc, 0, 1);
    wio = rb_io_get_write_io(io);
    if (wio == io && io == rb_stdin) wio = rb_stderr;
    prompt(argc, argv, wio);
    rb_io_flush(wio);
    str = rb_ensure(getpass_call, io, puts_call, wio);
    return str_chomp(str);
}

goto(line, column) → io click to toggle source

Set the cursor position at line and column.

You must require ‘io/console’ to use this method.

static VALUE
console_goto(VALUE io, VALUE y, VALUE x)
{
#ifdef _WIN32
    COORD pos;
    int fd = GetWriteFD(io);
    pos.X = NUM2UINT(x);
    pos.Y = NUM2UINT(y);
    if (!SetConsoleCursorPosition((HANDLE)rb_w32_get_osfhandle(fd), pos)) {
        rb_syserr_fail(LAST_ERROR, 0);
    }
#else
    rb_io_write(io, rb_sprintf(CSI "%d;%dH", NUM2UINT(y)+1, NUM2UINT(x)+1));
#endif
    return io;
}

goto_column(column) → io click to toggle source

Set the cursor position at column in the same line of the current position.

You must require ‘io/console’ to use this method.

static VALUE
console_goto_column(VALUE io, VALUE val)
{
#ifdef _WIN32
    HANDLE h;
    rb_console_size_t ws;
    COORD *pos = &ws.dwCursorPosition;

    h = (HANDLE)rb_w32_get_osfhandle(GetWriteFD(io));
    if (!GetConsoleScreenBufferInfo(h, &ws)) {
        rb_syserr_fail(LAST_ERROR, 0);
    }
    pos->X = NUM2INT(val);
    if (!SetConsoleCursorPosition(h, *pos)) {
        rb_syserr_fail(LAST_ERROR, 0);
    }
#else
    rb_io_write(io, rb_sprintf(CSI "%dG", NUM2UINT(val)+1));
#endif
    return io;
}

iflush click to toggle source

Flushes input buffer in kernel.

You must require ‘io/console’ to use this method.

static VALUE
console_iflush(VALUE io)
{
#if defined HAVE_TERMIOS_H || defined HAVE_TERMIO_H
    int fd = GetReadFD(io);
    if (tcflush(fd, TCIFLUSH)) sys_fail(io);
#endif

    return io;
}

ioflush click to toggle source

Flushes input and output buffers in kernel.

You must require ‘io/console’ to use this method.

static VALUE
console_ioflush(VALUE io)
{
#if defined HAVE_TERMIOS_H || defined HAVE_TERMIO_H
    int fd1 = GetReadFD(io);
    int fd2 = GetWriteFD(io);

    if (fd2 != -1 && fd1 != fd2) {
        if (tcflush(fd1, TCIFLUSH)) sys_fail(io);
        if (tcflush(fd2, TCOFLUSH)) sys_fail(io);
    }
    else {
        if (tcflush(fd1, TCIOFLUSH)) sys_fail(io);
    }
#endif

    return io;
}

noecho {|io| } click to toggle source

Yields self with disabling echo back.

STDIN.noecho(&:gets)

will read and return a line without echo back.

You must require ‘io/console’ to use this method.

static VALUE
console_noecho(VALUE io)
{
    return ttymode(io, rb_yield, io, set_noecho, NULL);
}

oflush click to toggle source

Flushes output buffer in kernel.

You must require ‘io/console’ to use this method.

static VALUE
console_oflush(VALUE io)
{
    int fd = GetWriteFD(io);
#if defined HAVE_TERMIOS_H || defined HAVE_TERMIO_H
    if (tcflush(fd, TCOFLUSH)) sys_fail(io);
#endif
    (void)fd;
    return io;
}

pressed?(key) → bool click to toggle source

Returns true if key is pressed. key may be a virtual key code or its name (String or Symbol) with out “VK_” prefix.

This method is Windows only.

You must require ‘io/console’ to use this method.

static VALUE
console_key_pressed_p(VALUE io, VALUE k)
{
    int vk = -1;

    if (FIXNUM_P(k)) {
        vk = NUM2UINT(k);
    }
    else {
        const struct vktable *t;
        const char *kn;
        if (SYMBOL_P(k)) {
            k = rb_sym2str(k);
            kn = RSTRING_PTR(k);
        }
        else {
            kn = StringValuePtr(k);
        }
        t = console_win32_vk(kn, RSTRING_LEN(k));
        if (!t || (vk = (short)t->vk) == -1) {
            rb_raise(rb_eArgError, "unknown virtual key code: % "PRIsVALUE, k);
        }
    }
    return GetKeyState(vk) & 0x80 ? Qtrue : Qfalse;
}

raw(min: nil, time: nil, intr: nil) {|io| } click to toggle source

Yields self within raw mode, and returns the result of the block.

STDIN.raw(&:gets)

will read and return a line without echo back and line editing.

The parameter min specifies the minimum number of bytes that should be received when a read operation is performed. (default: 1)

The parameter time specifies the timeout in seconds with a precision of 1/10 of a second. (default: 0)

If the parameter intr is true, enables break, interrupt, quit, and suspend special characters.

Refer to the manual page of termios for further details.

You must require ‘io/console’ to use this method.

static VALUE
console_raw(int argc, VALUE *argv, VALUE io)
{
    rawmode_arg_t opts, *optp = rawmode_opt(&argc, argv, 0, 0, &opts);
    return ttymode(io, rb_yield, io, set_rawmode, optp);
}

raw!(min: nil, time: nil, intr: nil) → io click to toggle source

Enables raw mode, and returns io.

If the terminal mode needs to be back, use io.raw { ... }.

See IO#raw for details on the parameters.

You must require ‘io/console’ to use this method.

static VALUE
console_set_raw(int argc, VALUE *argv, VALUE io)
{
    conmode t;
    rawmode_arg_t opts, *optp = rawmode_opt(&argc, argv, 0, 0, &opts);
    int fd = GetReadFD(io);
    if (!getattr(fd, &t)) sys_fail(io);
    set_rawmode(&t, optp);
    if (!setattr(fd, &t)) sys_fail(io);
    return io;
}

scroll_backward(n) → io click to toggle source

Scrolls the entire scrolls backward n lines.

You must require ‘io/console’ to use this method.

static VALUE
console_scroll_backward(VALUE io, VALUE val)
{
    return console_scroll(io, -NUM2INT(val));
}

scroll_forward(n) → io click to toggle source

Scrolls the entire scrolls forward n lines.

You must require ‘io/console’ to use this method.

static VALUE
console_scroll_forward(VALUE io, VALUE val)
{
    return console_scroll(io, +NUM2INT(val));
}

winsize → [rows, columns] click to toggle source

Returns console size.

You must require ‘io/console’ to use this method.

static VALUE
console_winsize(VALUE io)
{
    rb_console_size_t ws;
    int fd = GetWriteFD(io);
    if (!getwinsize(fd, &ws)) sys_fail(io);
    return rb_assoc_new(INT2NUM(winsize_row(&ws)), INT2NUM(winsize_col(&ws)));
}

winsize = [rows, columns] click to toggle source

Tries to set console size. The effect depends on the platform and the running environment.

You must require ‘io/console’ to use this method.

static VALUE
console_set_winsize(VALUE io, VALUE size)
{
    rb_console_size_t ws;
#if defined _WIN32
    HANDLE wh;
    int newrow, newcol;
    BOOL ret;
#endif
    VALUE row, col, xpixel, ypixel;
    const VALUE *sz;
    long sizelen;
    int fd;

    size = rb_Array(size);
    if ((sizelen = RARRAY_LEN(size)) != 2 && sizelen != 4) {
        rb_raise(rb_eArgError, "wrong number of arguments (given %ld, expected 2 or 4)", sizelen);
    }
    sz = RARRAY_CONST_PTR(size);
    row = sz[0], col = sz[1], xpixel = ypixel = Qnil;
    if (sizelen == 4) xpixel = sz[2], ypixel = sz[3];
    fd = GetWriteFD(io);
#if defined TIOCSWINSZ
    ws.ws_row = ws.ws_col = ws.ws_xpixel = ws.ws_ypixel = 0;
#define SET(m) ws.ws_##m = NIL_P(m) ? 0 : (unsigned short)NUM2UINT(m)
    SET(row);
    SET(col);
    SET(xpixel);
    SET(ypixel);
#undef SET
    if (!setwinsize(fd, &ws)) sys_fail(io);
#elif defined _WIN32
    wh = (HANDLE)rb_w32_get_osfhandle(fd);
#define SET(m) new##m = NIL_P(m) ? 0 : (unsigned short)NUM2UINT(m)
    SET(row);
    SET(col);
#undef SET
    if (!NIL_P(xpixel)) (void)NUM2UINT(xpixel);
    if (!NIL_P(ypixel)) (void)NUM2UINT(ypixel);
    if (!GetConsoleScreenBufferInfo(wh, &ws)) {
        rb_syserr_fail(LAST_ERROR, "GetConsoleScreenBufferInfo");
    }
    ws.dwSize.X = newcol;
    ret = SetConsoleScreenBufferSize(wh, ws.dwSize);
    ws.srWindow.Left = 0;
    ws.srWindow.Top = 0;
    ws.srWindow.Right = newcol-1;
    ws.srWindow.Bottom = newrow-1;
    if (!SetConsoleWindowInfo(wh, TRUE, &ws.srWindow)) {
        rb_syserr_fail(LAST_ERROR, "SetConsoleWindowInfo");
    }
    /* retry when shrinking buffer after shrunk window */
    if (!ret && !SetConsoleScreenBufferSize(wh, ws.dwSize)) {
        rb_syserr_fail(LAST_ERROR, "SetConsoleScreenBufferInfo");
    }
    /* remove scrollbar if possible */
    if (!SetConsoleWindowInfo(wh, TRUE, &ws.srWindow)) {
        rb_syserr_fail(LAST_ERROR, "SetConsoleWindowInfo");
    }
#endif
    return io;
}