PyMaemo/Accessing APIs without Python bindings - Revision history

213.150.1.132: /* Accessing Items in a GList */

2010-09-12T11:02:14Z

Accessing Items in a GList

← Older revision		Revision as of 11:02, 12 September 2010
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	Once you are done with the <code>GList</code> manipulation, you should free its memory:		Once you are done with the <code>GList</code> manipulation, you should free its memory:

			With some functions (NOT this one, see docs), you should also unref the list items first:
			<source lang="python">
			for i in glist(stuffs):
			gobject.g_object_unref(i)
			</source>

			Then free the list itself:
	<source lang="python">		<source lang="python">
	glib.g_list_free(contacts)		glib.g_list_free(contacts)
	</source>		</source>

	== Final Words ==		== Final Words ==

imported_>amigadave: use and


2010-06-22T12:10:14Z
use <source> and <code>
Show changes



imported_>frals: Undo revision 33973 --- unrelated link by spambot
2010-05-25T08:32:49Z
Undo revision 33973 --- unrelated link by spambot

				
				
				
				
				
				← Older revision
				Revision as of 08:32, 25 May 2010
				
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This document purpose is to give a basic understanding necessary to use ctypes to explore C libraries, specially ones that manipulate GObject. Notably, we do not describe how to define callbacks, but this is left as an exercise for the reader. Again, be sure to read the [http://docs.python.org/library/ctypes.html#callback-functions ctypes documentation] if you are interested in more advanced techniques. This document purpose is to give a basic understanding necessary to use ctypes to explore C libraries, specially ones that manipulate GObject. Notably, we do not describe how to define callbacks, but this is left as an exercise for the reader. Again, be sure to read the [http://docs.python.org/library/ctypes.html#callback-functions ctypes documentation] if you are interested in more advanced techniques.

==Related Links:== 

[http://www.bodybuildingrevealed.com/'''body building'''] 



See also more usage examples [[/More examples|here]]. See also more usage examples [[/More examples|here]].



[[Category:Python]] [[Category:Python]]



203.177.74.138 at 00:29, 7 May 2010
2010-05-07T00:29:27Z


				
				
				
				
				
				← Older revision
				Revision as of 00:29, 7 May 2010
				
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This document purpose is to give a basic understanding necessary to use ctypes to explore C libraries, specially ones that manipulate GObject. Notably, we do not describe how to define callbacks, but this is left as an exercise for the reader. Again, be sure to read the [http://docs.python.org/library/ctypes.html#callback-functions ctypes documentation] if you are interested in more advanced techniques. This document purpose is to give a basic understanding necessary to use ctypes to explore C libraries, specially ones that manipulate GObject. Notably, we do not describe how to define callbacks, but this is left as an exercise for the reader. Again, be sure to read the [http://docs.python.org/library/ctypes.html#callback-functions ctypes documentation] if you are interested in more advanced techniques.

==Related Links:==

[http://www.bodybuildingrevealed.com/'''body building''']



See also more usage examples [[/More examples|here]]. See also more usage examples [[/More examples|here]].



[[Category:Python]] [[Category:Python]]



imported_>lizardo: /* Accessing Items in a GList */
2010-04-12T14:09:36Z
Accessing Items in a GList

				
				
				
				
				
				← Older revision
				Revision as of 14:09, 12 April 2010
				
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  glib = ctypes.CDLL('libglib-2.0.so.0')   glib = ctypes.CDLL('libglib-2.0.so.0')
 
  def glist(addr):   def glist(addr):
     size = glib.g_list_length(addr) 
      class _GList(ctypes.Structure):       class _GList(ctypes.Structure):
          _fields_ = [('data', ctypes.c_void_p)]           _fields_ = [('data', ctypes.c_void_p),
     for i in xrange(0, size):                      ('next', ctypes.c_void_p)]
          item = glib.g_list_nth(addr, i)      l = addr
          yield _GList.from_address(item).data      while l:
          l = _GList.from_address(l)
          yield l.data
         l = l.next



This function uses the yield statement to construct a so called [http://docs.python.org/tutorial/classes.html#generators generator]. The actual GList manipulation is made using functions from libglib library. This generator makes it very easy to iterate over the items: This function uses the yield statement to construct a so called [http://docs.python.org/tutorial/classes.html#generators generator]. The actual GList manipulation is made using functions from libglib library. This generator makes it very easy to iterate over the items:



imported_>lizardo: /* Final Words */
2010-04-10T18:02:20Z
Final Words

				
				
				
				
				
				← Older revision
				Revision as of 18:02, 10 April 2010
				
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This document purpose is to give a basic understanding necessary to use ctypes to explore C libraries, specially ones that manipulate GObject. Notably, we do not describe how to define callbacks, but this is left as an exercise for the reader. Again, be sure to read the [http://docs.python.org/library/ctypes.html#callback-functions ctypes documentation] if you are interested in more advanced techniques. This document purpose is to give a basic understanding necessary to use ctypes to explore C libraries, specially ones that manipulate GObject. Notably, we do not describe how to define callbacks, but this is left as an exercise for the reader. Again, be sure to read the [http://docs.python.org/library/ctypes.html#callback-functions ctypes documentation] if you are interested in more advanced techniques.

See also more usage examples [[/More examples|here]].



[[Category:Python]] [[Category:Python]]



imported_>lizardo: /* Calling a Function Which Returns a GObject (i.e. a Constructor) */
2010-04-10T17:34:51Z
Calling a Function Which Returns a GObject (i.e. a Constructor)

				
				
				
				
				
				← Older revision
				Revision as of 17:34, 10 April 2010
				
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The byref() function returns a pointer to the given data. The hash() function returns the memory address of the argument. The byref() function returns a pointer to the given data. The hash() function returns the memory address of the argument.



== Calling a Function Which Returns a GObject (i.e. a Constructor) == == Calling a Function Which Returns a GObject ==



Every GObject instance created by a C library must have a corresponding Python object, so that it can be manipulated on Python code. This object, which acts like a "wrapper" around the C pointer, is created using the pygobject_new() C function. Unfortunately, pygobject_new() is not a plain function, but a macro which points to a function pointer in a struct (see /usr/include/pygtk-2.0/pygobject.h on the "#define pygobject_new ..." line), making it a little more complex to be called from Python. The snippet of code below, borrowed from [http://faq.pygtk.org/index.py?req=show&file=faq23.041.htp PyGTK FAQ], will take care of this: Every GObject instance created by a C library must have a corresponding Python object, so that it can be manipulated on Python code. This object, which acts like a "wrapper" around the C pointer, is created using the pygobject_new() C function. Unfortunately, pygobject_new() is not a plain function, but a macro which points to a function pointer in a struct (see /usr/include/pygtk-2.0/pygobject.h on the "#define pygobject_new ..." line), making it a little more complex to be called from Python. The snippet of code below, borrowed from [http://faq.pygtk.org/index.py?req=show&file=faq23.041.htp PyGTK FAQ], will take care of this:



imported_>amigadave: Category:Python
2010-02-11T15:46:25Z
Category:Python

				
				
				
				
				
				← Older revision
				Revision as of 15:46, 11 February 2010
				
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This document purpose is to give a basic understanding necessary to use ctypes to explore C libraries, specially ones that manipulate GObject. Notably, we do not describe how to define callbacks, but this is left as an exercise for the reader. Again, be sure to read the [http://docs.python.org/library/ctypes.html#callback-functions ctypes documentation] if you are interested in more advanced techniques. This document purpose is to give a basic understanding necessary to use ctypes to explore C libraries, specially ones that manipulate GObject. Notably, we do not describe how to define callbacks, but this is left as an exercise for the reader. Again, be sure to read the [http://docs.python.org/library/ctypes.html#callback-functions ctypes documentation] if you are interested in more advanced techniques.

[[Category:Python]]



imported_>lizardo: /* Calling a Function Which Returns a GObject (i.e. a Constructor) */
2010-02-02T13:14:33Z
Calling a Function Which Returns a GObject (i.e. a Constructor)

				
				
				
				
				
				← Older revision
				Revision as of 13:14, 2 February 2010
				
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  class PyGObjectCPAI(object):   class PyGObjectCPAI(object):
      def __init__(self):       def __init__(self):
         import gobject
          py_obj = ctypes.py_object(gobject._PyGObject_API)           py_obj = ctypes.py_object(gobject._PyGObject_API)
          addr = ctypes.pythonapi.PyCObject_AsVoidPtr(py_obj)           addr = ctypes.pythonapi.PyCObject_AsVoidPtr(py_obj)



imported_>lizardo: /* Initializing libosso-abook */
2010-02-02T13:14:11Z
Initializing libosso-abook

				
				
				
				
				
				← Older revision
				Revision as of 13:14, 2 February 2010
				
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  import sys   import sys
 import ctypes
 # be sure to import gtk before calling osso_abook_init()
 import gtk
       
  osso_abook = ctypes.CDLL('libosso-abook-1.0.so.0')   osso_abook = ctypes.CDLL('libosso-abook-1.0.so.0')

← Older revision		Revision as of 08:32, 25 May 2010
Line 139:		Line 139:

	This document purpose is to give a basic understanding necessary to use ctypes to explore C libraries, specially ones that manipulate GObject. Notably, we do not describe how to define callbacks, but this is left as an exercise for the reader. Again, be sure to read the [http://docs.python.org/library/ctypes.html#callback-functions ctypes documentation] if you are interested in more advanced techniques.		This document purpose is to give a basic understanding necessary to use ctypes to explore C libraries, specially ones that manipulate GObject. Notably, we do not describe how to define callbacks, but this is left as an exercise for the reader. Again, be sure to read the [http://docs.python.org/library/ctypes.html#callback-functions ctypes documentation] if you are interested in more advanced techniques.

	~~==Related Links:==~~

	~~[http://www.bodybuildingrevealed.com/'''body building''']~~

	See also more usage examples [[/More examples\|here]].		See also more usage examples [[/More examples\|here]].

	[[Category:Python]]		[[Category:Python]]

← Older revision		Revision as of 00:29, 7 May 2010
Line 139:		Line 139:

	This document purpose is to give a basic understanding necessary to use ctypes to explore C libraries, specially ones that manipulate GObject. Notably, we do not describe how to define callbacks, but this is left as an exercise for the reader. Again, be sure to read the [http://docs.python.org/library/ctypes.html#callback-functions ctypes documentation] if you are interested in more advanced techniques.		This document purpose is to give a basic understanding necessary to use ctypes to explore C libraries, specially ones that manipulate GObject. Notably, we do not describe how to define callbacks, but this is left as an exercise for the reader. Again, be sure to read the [http://docs.python.org/library/ctypes.html#callback-functions ctypes documentation] if you are interested in more advanced techniques.

			==Related Links:==

			[http://www.bodybuildingrevealed.com/'''body building''']

	See also more usage examples [[/More examples\|here]].		See also more usage examples [[/More examples\|here]].

	[[Category:Python]]		[[Category:Python]]

← Older revision		Revision as of 14:09, 12 April 2010
Line 113:		Line 113:

	glib = ctypes.CDLL('libglib-2.0.so.0')		glib = ctypes.CDLL('libglib-2.0.so.0')

	def glist(addr):		def glist(addr):
	~~size = glib.g_list_length(addr)~~
	class _GList(ctypes.Structure):		class _GList(ctypes.Structure):
	_fields_ = [('data', ctypes.c_void_p)]		_fields_ = [('data', ctypes.c_void_p),
	~~for i in xrange~~(0, ~~size~~):		('next', ctypes.c_void_p)]
	~~item~~ = ~~glib~~.~~g_list_nth~~(~~addr, i~~)		l = addr
	yield ~~_GList~~.~~from_address(item)~~.~~data~~		while l:
			l = _GList.from_address(l)
			yield l.data
			l = l.next

	This function uses the yield statement to construct a so called [http://docs.python.org/tutorial/classes.html#generators generator]. The actual GList manipulation is made using functions from libglib library. This generator makes it very easy to iterate over the items:		This function uses the yield statement to construct a so called [http://docs.python.org/tutorial/classes.html#generators generator]. The actual GList manipulation is made using functions from libglib library. This generator makes it very easy to iterate over the items:

← Older revision		Revision as of 18:02, 10 April 2010
Line 138:		Line 138:

	This document purpose is to give a basic understanding necessary to use ctypes to explore C libraries, specially ones that manipulate GObject. Notably, we do not describe how to define callbacks, but this is left as an exercise for the reader. Again, be sure to read the [http://docs.python.org/library/ctypes.html#callback-functions ctypes documentation] if you are interested in more advanced techniques.		This document purpose is to give a basic understanding necessary to use ctypes to explore C libraries, specially ones that manipulate GObject. Notably, we do not describe how to define callbacks, but this is left as an exercise for the reader. Again, be sure to read the [http://docs.python.org/library/ctypes.html#callback-functions ctypes documentation] if you are interested in more advanced techniques.

			See also more usage examples [[/More examples\|here]].

	[[Category:Python]]		[[Category:Python]]

← Older revision		Revision as of 17:34, 10 April 2010
Line 52:		Line 52:
	The byref() function returns a pointer to the given data. The hash() function returns the memory address of the argument.		The byref() function returns a pointer to the given data. The hash() function returns the memory address of the argument.

	== Calling a Function Which Returns a GObject ~~(i.e. a Constructor)~~ ==		== Calling a Function Which Returns a GObject ==

	Every GObject instance created by a C library must have a corresponding Python object, so that it can be manipulated on Python code. This object, which acts like a "wrapper" around the C pointer, is created using the pygobject_new() C function. Unfortunately, pygobject_new() is not a plain function, but a macro which points to a function pointer in a struct (see /usr/include/pygtk-2.0/pygobject.h on the "#define pygobject_new ..." line), making it a little more complex to be called from Python. The snippet of code below, borrowed from [http://faq.pygtk.org/index.py?req=show&file=faq23.041.htp PyGTK FAQ], will take care of this:		Every GObject instance created by a C library must have a corresponding Python object, so that it can be manipulated on Python code. This object, which acts like a "wrapper" around the C pointer, is created using the pygobject_new() C function. Unfortunately, pygobject_new() is not a plain function, but a macro which points to a function pointer in a struct (see /usr/include/pygtk-2.0/pygobject.h on the "#define pygobject_new ..." line), making it a little more complex to be called from Python. The snippet of code below, borrowed from [http://faq.pygtk.org/index.py?req=show&file=faq23.041.htp PyGTK FAQ], will take care of this:

← Older revision		Revision as of 15:46, 11 February 2010
Line 138:		Line 138:

	This document purpose is to give a basic understanding necessary to use ctypes to explore C libraries, specially ones that manipulate GObject. Notably, we do not describe how to define callbacks, but this is left as an exercise for the reader. Again, be sure to read the [http://docs.python.org/library/ctypes.html#callback-functions ctypes documentation] if you are interested in more advanced techniques.		This document purpose is to give a basic understanding necessary to use ctypes to explore C libraries, specially ones that manipulate GObject. Notably, we do not describe how to define callbacks, but this is left as an exercise for the reader. Again, be sure to read the [http://docs.python.org/library/ctypes.html#callback-functions ctypes documentation] if you are interested in more advanced techniques.

			[[Category:Python]]

← Older revision		Revision as of 13:14, 2 February 2010
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	class PyGObjectCPAI(object):		class PyGObjectCPAI(object):
	def __init__(self):		def __init__(self):
			import gobject
	py_obj = ctypes.py_object(gobject._PyGObject_API)		py_obj = ctypes.py_object(gobject._PyGObject_API)
	addr = ctypes.pythonapi.PyCObject_AsVoidPtr(py_obj)		addr = ctypes.pythonapi.PyCObject_AsVoidPtr(py_obj)

← Older revision		Revision as of 13:14, 2 February 2010
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	import sys		import sys
			import ctypes
			# be sure to import gtk before calling osso_abook_init()
			import gtk

	osso_abook = ctypes.CDLL('libosso-abook-1.0.so.0')		osso_abook = ctypes.CDLL('libosso-abook-1.0.so.0')