IO#isatty

static VALUE
console_platform_tty_p(int argc, VALUE *argv, VALUE io)
{
    VALUE ret = Qfalse;
    int mode = 0;

    if (argc > 0) {
        int i;
        for (i = 0; i < argc; ++i) {
            VALUE m = argv[i];
            if (NIL_P(m)) {
                mode |= platform_default_bit;
                continue;
            }
            Check_Type(m, T_SYMBOL);
            if (m == ID2SYM(rb_intern("any"))) {
                mode |= platform_any_bit;
            }
#if defined _WIN32
            else if (m == ID2SYM(rb_intern("cygwin"))) {
                mode |= platform_cygwin_bit;
            }
            else if (m == ID2SYM(rb_intern("msys"))) {
                mode |= platform_msys_bit;
            }
#endif
            else {
                rb_raise(rb_eArgError, "unknown tty type: %+" PRIsVALUE, m);
            }
        }
    }
    if ((mode & platform_default_bit) || (mode == 0)) {
        ret = rb_call_super(0, 0);
    }
    if ((mode & ~platform_default_bit) && !RTEST(ret)) {
#if defined _WIN32
        if (mode & (platform_cygwin_bit | platform_msys_bit)) {
            struct {
                FILE_NAME_INFO info;
                WCHAR rest[MAX_PATH];
            } buffer;

            HANDLE h = (HANDLE)rb_w32_get_osfhandle(GetReadFD(io));
            if ((GetFileType(h) == FILE_TYPE_PIPE) &&
                GetFileInformationByHandleEx(h, FileNameInfo, &buffer, sizeof(buffer))) {
                WCHAR *const name = buffer.info.FileName;
                DWORD len = buffer.info.FileNameLength / sizeof(WCHAR);
                name[len] = L'\0';
# define tty_pipe_p(type) \
                (memcmp(name, L"\\" #type "-", sizeof(L"\\" #type)) == 0 && \
                 wcsstr(&name[rb_strlen_lit("\\" #type "-")], L"-pty") != NULL)
                if (!ret && (mode & platform_cygwin_bit)) {
                    ret = tty_pipe_p(cygwin);
                }
                if (!ret && (mode & platform_msys_bit)) {
                    ret = tty_pipe_p(msys);
                }
            }
        }
#endif
    }
    return ret;
}