********** wx.Process ********** Inheritance diagram for `wx.Process`: | .. inheritance-diagram:: wx.Process | Description =========== The objects of this class are used in conjunction with the `wx.Execute <../wxFunctions.html#Execute>`_ function. When a `wx.Process` object is passed to `wx.Execute`, its `OnTerminate <#OnTerminate>`_ virtual method is called when the process terminates. This allows the program to be (asynchronously) notified about the process termination and also retrieve its exit status which is unavailable from `wx.Execute` in the case of asynchronous execution. Please note that if the process termination notification is processed by the parent, it is responsible for deleting the `wx.Process` object which sent it. However, if it is not processed, the object will delete itself and so the library users should only delete those objects whose notifications have been processed (and call `Detach <#Detach>`_ for others). `wx.Process` also supports IO redirection of the child process. For this, you have to call its `Redirect <#Redirect>`_ method before passing it to `wx.Execute <../wxFunctions.html#Execute>`_. If the child process was launched successfully, `GetInputStream <#GetInputStream>`_, `GetOutputStream <#GetOutputStream>`_ and `GetErrorStream <#GetErrorStream>`_ can then be used to retrieve the streams corresponding to the child process standard output, input and error output respectively. .. seealso:: `wx.Execute <../wxFunctions.html#Execute>`_ Derived From ^^^^^^^^^^^^^ * `wx.EvtHandler `_ Methods Summary ^^^^^^^^^^^^^^^ * `__init__ <#__init__>`_ * `CloseOutput <#CloseOutput>`_ * `Detach <#Detach>`_ * `Exists <#Exists>`_ * `GetErrorStream <#GetErrorStream>`_ * `GetInputStream <#GetInputStream>`_ * `GetOutputStream <#GetOutputStream>`_ * `GetPid <#GetPid>`_ * `IsErrorAvailable <#IsErrorAvailable>`_ * `IsInputAvailable <#IsInputAvailable>`_ * `IsInputOpened <#IsInputOpened>`_ * `IsRedirected <#IsRedirected>`_ * `Kill <#Kill>`_ * `OnTerminate <#OnTerminate>`_ * `Open <#Open>`_ * `Redirect <#Redirect>`_ Properties Summary ^^^^^^^^^^^^^^^^^^ * `ErrorAvailable <#ErrorAvailable>`_ * `ErrorStream <#ErrorStream>`_ * `InputAvailable <#InputAvailable>`_ * `InputOpened <#InputOpened>`_ * `InputStream <#InputStream>`_ * `OutputStream <#OutputStream>`_ Class API ========= Methods ^^^^^^^ .. method:: __init__(parent=None, id=-1) Constructs a process object. `id` is only used in the case you want to use wxPython events. It identifies this object, or another window that will receive the event. If the parent parameter is not ``None``, it will receive a ``wx.EVT_END_PROCESS`` notification event (you should bind the ``wx.EVT_END_PROCESS`` event in the parent to handle it) with the given id. **Parameters:** * `parent` (`wx.EvtHandler `_): the event handler parent. * `id` (int): The event id. | **Returns:** `wx.Process `_ -------- .. method:: CloseOutput() Closes the output stream (the one connected to the stdin of the child process). This function can be used to indicate to the child process that there is no more data to be read -- usually, a filter program will only terminate when the input stream is closed. -------- .. method:: Detach() Normally, a `wx.Process` object is deleted by its parent when it receives the notification about the process termination. However, it might happen that the parent object is destroyed before the external process is terminated (e.g. a window from which this external process was launched is closed by the user) and in this case it **should not delete** the `wx.Process` object, but **should call** `Detach()` instead. After the `wx.Process` object is detached from its parent, no notification events will be sent to the parent and the object will delete itself upon reception of the process termination notification. -------- .. method:: Exists(pid) Returns ``True`` if the given process exists in the system. **Parameters:** * `pid` (int) | **Returns:** `bool` .. seealso:: `Kill <#Kill>`_ -------- .. method:: GetErrorStream() Returns an input stream which corresponds to the standard error output (``stderr``) of the child process. | **Returns:** `wx.InputStream `_ -------- .. method:: GetInputStream() It returns an input stream corresponding to the standard output stream of the subprocess. If it is ``None``, you have not turned on the redirection. | **Returns:** `wx.InputStream `_ .. seealso:: `Redirect <#Redirect>`_ -------- .. method:: GetOutputStream() It returns an output stream correspoding to the input stream of the subprocess. If it is ``None``, you have not turned on the redirection. | **Returns:** `wx.OutputStream `_ .. seealso:: `Redirect <#Redirect>`_ -------- .. method:: GetPid() Returns the process ID of the process launched by `Open <#Open>`_. | **Returns:** `long` -------- .. method:: IsErrorAvailable() Returns ``True`` if there is data to be read on the child process standard error stream. | **Returns:** `bool` .. seealso:: `IsInputAvailable <#IsInputAvailable>`_ -------- .. method:: IsInputAvailable() Returns ``True`` if there is data to be read on the child process standard output stream. This allows to write simple (and extremely inefficient) polling-based code waiting for a better mechanism in future wxWidgets versions. | **Returns:** `bool` .. seealso:: `IsInputOpened <#IsInputOpened>`_ -------- .. method:: IsInputOpened() Returns ``True`` if the child process standard output stream is opened. | **Returns:** `bool` -------- .. method:: IsRedirected() `No docstrings available for this method.` -------- .. method:: Kill(pid, signal=wx.SIGNONE, flags=wx.KILL_NOCHILDREN) Send the specified signal to the given process. **Parameters:** * `pid` (int): the process id. * `signal` (int): Possible `signal` values are: * ``wx.SIGNONE`` = 0 ---> verify if the process exists under Unix * ``wx.SIGHUP`` * ``wx.SIGINT`` * ``wx.SIGQUIT`` * ``wx.SIGILL`` * ``wx.SIGTRAP`` * ``wx.SIGABRT`` * ``wx.SIGEMT`` * ``wx.SIGFPE`` * ``wx.SIGKILL`` ---> forcefully kill, dangerous! * ``wx.SIGBUS`` * ``wx.SIGSEGV`` * ``wx.SIGSYS`` * ``wx.SIGPIPE`` * ``wx.SIGALRM`` * ``wx.SIGTERM`` ---> terminate the process gently ``wx.SIGNONE``, ``wx.SIGKILL`` and ``wx.SIGTERM`` have the same meaning under both Unix and Windows but all the other signals are equivalent to ``wx.SIGTERM`` under Windows. * `flags` (int): The `flags` parameter can be ``wx.KILL_NOCHILDREN`` (the default), or ``wx.KILL_CHILDREN``, in which case the child processes of this process will be killed too. Note that under Unix, for ``wx.KILL_CHILDREN`` to work you should have created the process passing ``wx.EXEC_MAKE_GROUP_LEADER``. Returns one of the following flags: ========================= ====================== Kill Error Flags Description ========================= ====================== ``wx.KILL_OK`` no error ``wx.KILL_BAD_SIGNAL`` no such signal ``wx.KILL_ACCESS_DENIED`` permission denied ``wx.KILL_NO_PROCESS`` no such process ``wx.KILL_ERROR`` another, unspecified error ========================= ====================== | **Returns:** `int` .. seealso:: `Exists <#Exists>`_, `wx.Kill `_ -------- .. method:: OnTerminate(status) It is called when the process with the pid **Parameters:** * `status` (int): The exit code of the process. -------- .. method:: Open(cmd, flags=wx.EXEC_ASYNC) This static method replaces the standard ``popen()`` function: it launches the process specified by the `cmd` parameter and returns the `wx.Process` object which can be used to retrieve the streams connected to the standard input, output and error output of the child process. If the process couldn't be launched, ``None`` is returned. **Parameters:** * `cmd` (string): The command to execute, including optional arguments. * `flags` (int): The flags to pass to `wx.Execute <../wxFunctions.html#Execute>`_. .. note:: ``wx.EXEC_SYNC`` should not be used | **Returns:** `wx.Process `_ .. note:: Note that in any case the returned pointer should **not** be deleted, rather the process object will be destroyed automatically when the child process terminates. This does mean that the child process should be told to quit before the main program exits to avoid memory leaks. .. seealso:: `wx.Execute <../wxFunctions.html#Execute>`_ -------- .. method:: Redirect() Turns on redirection. `wx.Execute <../wxFunctions.html#Execute>`_ will try to open a couple of pipes to catch the subprocess `stdio`. The caught input stream is returned by `GetOutputStream()` as a non-seekable stream. The caught output stream is returned by `GetInputStream()` as a non-seekable stream. -------- Properties ^^^^^^^^^^ .. attribute:: ErrorAvailable .. attribute:: ErrorStream See `GetErrorStream <#GetErrorStream>`_ .. attribute:: InputAvailable .. attribute:: InputOpened .. attribute:: InputStream See `GetInputStream <#GetInputStream>`_ .. attribute:: OutputStream See `GetOutputStream <#GetOutputStream>`_