Python os.O_NONBLOCK Examples

def __connect(self):
        device_addr, hidraw_device, event_device = self.__find_device()
        if device_addr is None:
            return False
        self.__report_fd = os.open(hidraw_device, os.O_RDWR | os.O_NONBLOCK)
        self.__fd = FileIO(self.__report_fd, "rb+", closefd=False)
        self.__input_device = InputDevice(event_device)
        self.__input_device.grab()
        buf = bytearray(38)
        buf[0] = 0x02
        try:
            return bool(fcntl.ioctl(self.__fd, 3223734279, bytes(buf)))
        except:
            pass
        if self.recv():
            self.update_controller() 

def _make_non_blocking(file_obj):
    """make file object non-blocking
    Windows doesn't have the fcntl module, but someone on
    stack overflow supplied this code as an answer, and it works
    http://stackoverflow.com/a/34504971/2893090"""

    if USING_WINDOWS:
        LPDWORD = POINTER(DWORD)
        PIPE_NOWAIT = wintypes.DWORD(0x00000001)

        SetNamedPipeHandleState = windll.kernel32.SetNamedPipeHandleState
        SetNamedPipeHandleState.argtypes = [HANDLE, LPDWORD, LPDWORD, LPDWORD]
        SetNamedPipeHandleState.restype = BOOL

        h = msvcrt.get_osfhandle(file_obj.fileno())

        res = windll.kernel32.SetNamedPipeHandleState(h, byref(PIPE_NOWAIT), None, None)
        if res == 0:
            raise ValueError(WinError())

    else:
        # Set the file status flag (F_SETFL) on the pipes to be non-blocking
        # so we can attempt to read from a pipe with no new data without locking
        # the program up
        fcntl.fcntl(file_obj, fcntl.F_SETFL, os.O_NONBLOCK) 

def _pipe2_by_pipe(flags):
    """A ``pipe2`` implementation using :func:`os.pipe`.

    ``flags`` is an integer providing the flags to ``pipe2``.

    .. warning::

       This implementation is not atomic!

    Return a pair of file descriptors ``(r, w)``.

    """
    fds = os.pipe()
    if flags & os.O_NONBLOCK != 0:
        for fd in fds:
            set_fd_status_flag(fd, os.O_NONBLOCK)
    if flags & O_CLOEXEC != 0:
        for fd in fds:
            set_fd_flag(fd, O_CLOEXEC)
    return fds 

def freebsd_tun_alloc(self, dev, flags):
		try:
			sockfd = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
			ifr = struct.pack('<16si', 'tun', 0)
			self.iface_name = fcntl.ioctl(sockfd, self.IOCTL_FREEBSD_SIOCIFCREATE2, ifr)
			self.iface_name = self.iface_name.rstrip("\x00")

			buff = array.array('c', dev+"\x00")
			caddr_t, _ = buff.buffer_info()
			ifr = struct.pack('16sP', self.iface_name, caddr_t);

			fcntl.ioctl(sockfd, self.IOCTL_FREEBSD_SIOCSIFNAME, ifr)
			tun = os.open("/dev/"+self.iface_name, os.O_RDWR | os.O_NONBLOCK)
			self.iface_name = dev

		except IOError as e:
			print e
			common.internal_print("Error: Cannot create tunnel. Is {0} in use?".format(dev), -1)
			sys.exit(-1)

		return tun 

def start(self):
        """
        Start this monitor.

        The monitor will not receive events until this method is called. This
        method does nothing if called on an already started :class:`Monitor`.

        .. note::

           Typically you don't need to call this method. It is implicitly
           called by :meth:`poll()` and :meth:`__iter__()`.

        .. seealso:: :attr:`started`
        .. versionchanged:: 0.16
           This method does nothing if the :class:`Monitor` was already
           started.
        """
        if not self._started:
            self._libudev.udev_monitor_enable_receiving(self)
            # Force monitor FD into non-blocking mode
            pipe.set_fd_status_flag(self, os.O_NONBLOCK)
            self._started = True 

def start(self) -> None:
        self.current_frame = [0 for _ in range(self.bars)]
        self.growing_frame = b""
        try:
            # delete old contents of the pipe
            os.remove(self.cava_fifo_path)
        except FileNotFoundError:
            # the file does not exist
            pass
        try:
            os.mkfifo(self.cava_fifo_path)
        except FileExistsError:
            # the file already exists
            logging.info("%s already exists while starting", self.cava_fifo_path)

        self.cava_process = subprocess.Popen(
            ["cava", "-p", os.path.join(settings.BASE_DIR, "config/cava.config")],
            cwd=settings.BASE_DIR,
        )
        # cava_fifo = open(cava_fifo_path, 'r')
        self.cava_fifo = os.open(self.cava_fifo_path, os.O_RDONLY | os.O_NONBLOCK) 

def read_char_no_blocking():
    ''' Read a character in nonblocking mode, if no characters are present in the buffer, return an empty string '''
    fd = sys.stdin.fileno()
    old_settings = termios.tcgetattr(fd)
    old_flags = fcntl.fcntl(fd, fcntl.F_GETFL)
    try:
        tty.setraw(fd, termios.TCSADRAIN)
        fcntl.fcntl(fd, fcntl.F_SETFL, old_flags | os.O_NONBLOCK)
        return sys.stdin.read(1)
    except IOError as e:
        ErrorNumber = e[0]
        # IOError with ErrorNumber 11(35 in Mac)  is thrown when there is nothing to read(Resource temporarily unavailable)
        if (sys.platform.startswith("linux") and ErrorNumber != 11) or (sys.platform == "darwin" and ErrorNumber != 35):
            raise
        return ""
    finally:
        fcntl.fcntl(fd, fcntl.F_SETFL, old_flags)
        termios.tcsetattr(fd, termios.TCSADRAIN, old_settings) 

def train(self):
        i=0
        if(self.args.ipython):
            import fcntl
            fd = sys.stdin.fileno()
            fl = fcntl.fcntl(fd, fcntl.F_GETFL)
            fcntl.fcntl(fd, fcntl.F_SETFL, fl | os.O_NONBLOCK)

        while((i < self.total_steps or self.total_steps == -1) and not self.gan.destroy):
            i+=1
            start_time = time.time()
            self.step()
            GlobalViewer.tick()

            if (self.args.save_every != None and
                self.args.save_every != -1 and
                self.args.save_every > 0 and
                i % self.args.save_every == 0):
                print(" |= Saving network")
                self.gan.save(self.save_file)
            if self.args.ipython:
                self.check_stdin()
            end_time = time.time() 

def blocking(self, port, mode=False):
        """
        Set port function mode blocking/nonblocking

        :param port: port to set mode
        :param mode: False to set nonblock mode, True for block mode
        """
        fd = self._open([port])[0]

        try:
            fl = fcntl.fcntl(fd, fcntl.F_GETFL)
            if not mode:
                fcntl.fcntl(fd, fcntl.F_SETFL, fl | os.O_NONBLOCK)
            else:
                fcntl.fcntl(fd, fcntl.F_SETFL, fl & ~os.O_NONBLOCK)

        except Exception as inst:
            print("FAIL: Setting (non)blocking mode: " + str(inst))
            return

        if mode:
            print("PASS: set to blocking mode")
        else:
            print("PASS: set to nonblocking mode") 

def test_fcntl_bad_file(self):
        class F:
            def __init__(self, fn):
                self.fn = fn
            def fileno(self):
                return self.fn
        self.assertRaises(ValueError, fcntl.fcntl, -1, fcntl.F_SETFL, os.O_NONBLOCK)
        self.assertRaises(ValueError, fcntl.fcntl, F(-1), fcntl.F_SETFL, os.O_NONBLOCK)
        self.assertRaises(TypeError, fcntl.fcntl, 'spam', fcntl.F_SETFL, os.O_NONBLOCK)
        self.assertRaises(TypeError, fcntl.fcntl, F('spam'), fcntl.F_SETFL, os.O_NONBLOCK)
        # Issue 15989
        self.assertRaises(ValueError, fcntl.fcntl, _testcapi.INT_MAX + 1,
                                                   fcntl.F_SETFL, os.O_NONBLOCK)
        self.assertRaises(ValueError, fcntl.fcntl, F(_testcapi.INT_MAX + 1),
                                                   fcntl.F_SETFL, os.O_NONBLOCK)
        self.assertRaises(ValueError, fcntl.fcntl, _testcapi.INT_MIN - 1,
                                                   fcntl.F_SETFL, os.O_NONBLOCK)
        self.assertRaises(ValueError, fcntl.fcntl, F(_testcapi.INT_MIN - 1),
                                                   fcntl.F_SETFL, os.O_NONBLOCK) 

def follow_file(filename):
    while True:
        try:
            fd = os.open(filename, os.O_RDONLY | os.O_NONBLOCK)
        except OSError:
            yield None
            continue

        try:
            inode = os.fstat(fd).st_ino
            first = True

            while True:
                try:
                    stat = os.stat(filename)
                except OSError:
                    stat = None

                yield first, time.time(), fd
                if stat is None or inode != stat.st_ino:
                    break

                first = False
        finally:
            os.close(fd) 

def _openTunnel(self, name, mode):
        """
        Open the named tunnel using the given mode.

        @param name: The name of the tunnel to open.
        @type name: L{bytes}

        @param mode: Flags from L{TunnelFlags} with exactly one of
            L{TunnelFlags.IFF_TUN} or L{TunnelFlags.IFF_TAP} set.

        @return: A L{_TunnelDescription} representing the newly opened tunnel.
        """
        flags = (
            self._system.O_RDWR | self._system.O_CLOEXEC |
            self._system.O_NONBLOCK)
        config = struct.pack("%dsH" % (_IFNAMSIZ,), name, mode.value)
        fileno = self._system.open(_TUN_KO_PATH, flags)
        result = self._system.ioctl(fileno, _TUNSETIFF, config)
        return _TunnelDescription(fileno, result[:_IFNAMSIZ].strip(b'\x00')) 

def test_startListeningOpensDevice(self):
        """
        L{TuntapPort.startListening} opens the tunnel factory character special
        device C{"/dev/net/tun"} and configures it as a I{tun} tunnel.
        """
        system = self.system
        self.port.startListening()
        tunnel = self.system.getTunnel(self.port)

        expected = (
            system.O_RDWR | system.O_CLOEXEC | system.O_NONBLOCK,
            b"tun0" + b"\x00" * (_IFNAMSIZ - len(b"tun0")),
            self.port.interface, False, True)
        actual = (
            tunnel.openFlags,
            tunnel.requestedName,
            tunnel.name, tunnel.blocking, tunnel.closeOnExec)
        self.assertEqual(expected, actual) 

def make_nonblocking(fd):
        """Put the file descriptor *fd* into non-blocking mode if possible.

        :return: A boolean value that evaluates to True if successful."""
        flags = fcntl.fcntl(fd, fcntl.F_GETFL, 0)
        if not bool(flags & os.O_NONBLOCK):
            fcntl.fcntl(fd, fcntl.F_SETFL, flags | os.O_NONBLOCK)
            return True 

def test_fcntl_bad_file(self):
        with self.assertRaises(ValueError):
            fcntl.fcntl(-1, fcntl.F_SETFL, os.O_NONBLOCK)
        with self.assertRaises(ValueError):
            fcntl.fcntl(BadFile(-1), fcntl.F_SETFL, os.O_NONBLOCK)
        with self.assertRaises(TypeError):
            fcntl.fcntl('spam', fcntl.F_SETFL, os.O_NONBLOCK)
        with self.assertRaises(TypeError):
            fcntl.fcntl(BadFile('spam'), fcntl.F_SETFL, os.O_NONBLOCK) 

def test_fcntl_fileno(self):
        # the example from the library docs
        self.f = open(TESTFN, 'w')
        rv = fcntl.fcntl(self.f.fileno(), fcntl.F_SETFL, os.O_NONBLOCK)
        if verbose:
            print 'Status from fcntl with O_NONBLOCK: ', rv
        if sys.platform not in ['os2emx']:
            rv = fcntl.fcntl(self.f.fileno(), fcntl.F_SETLKW, lockdata)
            if verbose:
                print 'String from fcntl with F_SETLKW: ', repr(rv)
        self.f.close() 

def test_basic(self):
        try:
            debug("Calling master_open()")
            master_fd, slave_name = pty.master_open()
            debug("Got master_fd '%d', slave_name '%s'" %
                  (master_fd, slave_name))
            debug("Calling slave_open(%r)" % (slave_name,))
            slave_fd = pty.slave_open(slave_name)
            debug("Got slave_fd '%d'" % slave_fd)
        except OSError:
            # " An optional feature could not be imported " ... ?
            raise unittest.SkipTest, "Pseudo-terminals (seemingly) not functional."

        self.assertTrue(os.isatty(slave_fd), 'slave_fd is not a tty')

        # Solaris requires reading the fd before anything is returned.
        # My guess is that since we open and close the slave fd
        # in master_open(), we need to read the EOF.

        # Ensure the fd is non-blocking in case there's nothing to read.
        orig_flags = fcntl.fcntl(master_fd, fcntl.F_GETFL)
        fcntl.fcntl(master_fd, fcntl.F_SETFL, orig_flags | os.O_NONBLOCK)
        try:
            s1 = os.read(master_fd, 1024)
            self.assertEqual('', s1)
        except OSError, e:
            if e.errno != errno.EAGAIN:
                raise
        # Restore the original flags. 

def _set_non_blocking(self, fd):
        flags = fcntl.fcntl(fd, fcntl.F_GETFL)
        self.assertNotEqual(flags, -1)
        res = fcntl.fcntl(fd, fcntl.F_SETFL, flags | os.O_NONBLOCK)
        self.assertEqual(res, 0) 

def setUp(self):
        import fcntl

        self.alrm = signal.signal(signal.SIGALRM, lambda x,y:None)
        self.read, self.write = os.pipe()
        flags = fcntl.fcntl(self.write, fcntl.F_GETFL, 0)
        flags = flags | os.O_NONBLOCK
        fcntl.fcntl(self.write, fcntl.F_SETFL, flags)
        self.old_wakeup = signal.set_wakeup_fd(self.write) 

def __init__(self, fd, map=None):
            dispatcher.__init__(self, None, map)
            self.connected = True
            try:
                fd = fd.fileno()
            except AttributeError:
                pass
            self.set_file(fd)
            # set it to non-blocking mode
            flags = fcntl.fcntl(fd, fcntl.F_GETFL, 0)
            flags = flags | os.O_NONBLOCK
            fcntl.fcntl(fd, fcntl.F_SETFL, flags) 

def _set_nonblocking(self, fd):
        flags = fcntl.fcntl(fd, fcntl.F_GETFL)
        fcntl.fcntl(fd, fcntl.F_SETFL, flags | os.O_NONBLOCK) 

def _set_nonblocking(fd):
    flags = fcntl.fcntl(fd, fcntl.F_GETFL)
    fcntl.fcntl(fd, fcntl.F_SETFL, flags | os.O_NONBLOCK) 

def _set_nonblocking(self, fd):
        flags = fcntl.fcntl(fd, fcntl.F_GETFL)
        fcntl.fcntl(fd, fcntl.F_SETFL, flags | os.O_NONBLOCK) 

def _set_nonblocking(fd):
    flags = fcntl.fcntl(fd, fcntl.F_GETFL)
    fcntl.fcntl(fd, fcntl.F_SETFL, flags | os.O_NONBLOCK) 

def _set_nonblocking(fd):
    flags = fcntl.fcntl(fd, fcntl.F_GETFL)
    fcntl.fcntl(fd, fcntl.F_SETFL, flags | os.O_NONBLOCK) 

def cmd_run(app, cmd):
    """e.g.: piku run <app> ls -- -al"""

    app = exit_if_invalid(app)

    config_file = join(ENV_ROOT, app, 'LIVE_ENV')
    environ.update(parse_settings(config_file))
    for f in [stdout, stderr]:
        fl = fcntl(f, F_GETFL)
        fcntl(f, F_SETFL, fl | O_NONBLOCK)
    p = Popen(' '.join(cmd), stdin=stdin, stdout=stdout, stderr=stderr, env=environ, cwd=join(APP_ROOT, app), shell=True)
    p.communicate() 

def test_osshlock(self):
        if hasattr(posix, "O_SHLOCK"):
            fd1 = os.open(test_support.TESTFN,
                         os.O_WRONLY|os.O_SHLOCK|os.O_CREAT)
            fd2 = os.open(test_support.TESTFN,
                          os.O_WRONLY|os.O_SHLOCK|os.O_CREAT)
            os.close(fd2)
            os.close(fd1)

            if hasattr(posix, "O_EXLOCK"):
                fd = os.open(test_support.TESTFN,
                             os.O_WRONLY|os.O_SHLOCK|os.O_CREAT)
                self.assertRaises(OSError, os.open, test_support.TESTFN,
                                  os.O_RDONLY|os.O_EXLOCK|os.O_NONBLOCK)
                os.close(fd) 

def test_osexlock(self):
        if hasattr(posix, "O_EXLOCK"):
            fd = os.open(test_support.TESTFN,
                         os.O_WRONLY|os.O_EXLOCK|os.O_CREAT)
            self.assertRaises(OSError, os.open, test_support.TESTFN,
                              os.O_WRONLY|os.O_EXLOCK|os.O_NONBLOCK)
            os.close(fd)

            if hasattr(posix, "O_SHLOCK"):
                fd = os.open(test_support.TESTFN,
                             os.O_WRONLY|os.O_SHLOCK|os.O_CREAT)
                self.assertRaises(OSError, os.open, test_support.TESTFN,
                                  os.O_WRONLY|os.O_EXLOCK|os.O_NONBLOCK)
                os.close(fd) 

def test_fcntl_fileno(self):
        # the example from the library docs
        self.f = open(TESTFN, 'w')
        rv = fcntl.fcntl(self.f.fileno(), fcntl.F_SETFL, os.O_NONBLOCK)
        if verbose:
            print 'Status from fcntl with O_NONBLOCK: ', rv
        if sys.platform not in ['os2emx']:
            rv = fcntl.fcntl(self.f.fileno(), fcntl.F_SETLKW, lockdata)
            if verbose:
                print 'String from fcntl with F_SETLKW: ', repr(rv)
        self.f.close() 

def test_fcntl_bad_file_overflow(self):
        from _testcapi import INT_MAX, INT_MIN
        # Issue 15989
        with self.assertRaises(ValueError):
            fcntl.fcntl(INT_MAX + 1, fcntl.F_SETFL, os.O_NONBLOCK)
        with self.assertRaises(ValueError):
            fcntl.fcntl(BadFile(INT_MAX + 1), fcntl.F_SETFL, os.O_NONBLOCK)
        with self.assertRaises(ValueError):
            fcntl.fcntl(INT_MIN - 1, fcntl.F_SETFL, os.O_NONBLOCK)
        with self.assertRaises(ValueError):
            fcntl.fcntl(BadFile(INT_MIN - 1), fcntl.F_SETFL, os.O_NONBLOCK)