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wx.LogChain
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Inheritance diagram for `wx.LogChain`:

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.. inheritance-diagram:: wx.LogChain

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Description
===========

This simple class allows to chain log sinks, that is to install a new sink but keep passing log messages to the old one instead 
of replacing it completely as `wx.Log.SetActiveTarget <wx.Log.html#SetActiveTarget>`_ does.

It is especially useful when you want to divert the logs somewhere (for example to a file or a log window) but also keep showing 
the error messages using the standard dialogs as `wx.LogGui <wx.LogGui.html>`_ does by default.

Example of usage::


    logChain = wx.LogChain(wx.LogStderr())  

    # All the log messages are sent to stderr and also processed as usually ...  

    ProcessMessage()

    # Don't delete logChain directly as this would leave a dangling
    # pointer as active log target, use SetActiveTarget() instead 

    del wx.Log.SetActiveTarget(None)


Derived From
^^^^^^^^^^^^^

* `wx.Log <wx.Log.html>`_ 


Methods Summary
^^^^^^^^^^^^^^^

* `__init__ <#__init__>`_ 
* `DetachOldLog <#DetachOldLog>`_ 
* `GetOldLog <#GetOldLog>`_ 
* `IsPassingMessages <#IsPassingMessages>`_ 
* `PassMessages <#PassMessages>`_ 
* `SetLog <#SetLog>`_ 

Properties Summary
^^^^^^^^^^^^^^^^^^

* `OldLog <#OldLog>`_ 

Class API
=========

Methods
^^^^^^^


.. method:: __init__(logger)

   Sets the specified logger (which may be ``None``) as the default log target but the log messages are also passed to the previous log target if any.

   **Parameters:**

   * `logger` (`wx.Log <wx.Log.html>`_)

   |

   **Returns:**

   `wx.LogChain <wx.LogChain.html>`_
 

--------

.. method:: DetachOldLog()

   Detaches the old log target so it won't be destroyed when the `wx.LogChain` object is destroyed.


--------

.. method:: GetOldLog()

   Returns the pointer to the previously active log target (which may be ``None``).

   |  

   **Returns:**

   `wx.Log <wx.Log.html>`_
 

--------

.. method:: IsPassingMessages()

   Returns ``True`` if the messages are passed to the previously active log target (default) or ``False`` if `PassMessages <#PassMessages>`_ had been called.

   |  

   **Returns:**

   `bool` 

--------

.. method:: PassMessages(passMessages)

   By default, the log messages are passed to the previously active log target. Calling this function with ``False`` 
   parameter disables this behaviour (presumably temporarily, as you shouldn't use `wx.LogChain` at all otherwise) and it 
   can be reenabled by calling it again with `passMessages` set to ``True``.

   **Parameters:**

   * `passMessages` (bool) 

--------

.. method:: SetLog(logger)

   Sets another log target to use (may be ``None``). The log target specified in the constructor or in a previous call to this function is deleted.

   This doesn't change the old log target value (the one the messages are forwarded to) which still remains the same as was active when `wx.LogChain` object was created.

   **Parameters:**

   * `logger` (`wx.Log <wx.Log.html>`_) 

--------

Properties
^^^^^^^^^^


.. attribute:: OldLog

   See `GetOldLog <#GetOldLog>`_