🌐 Mailman 3 January 2009 - Python-list - python.org

Re: How to declare python ints in C extensions?
by Tony Houghton Jan. 5, 2009

Jan. 5, 2009

On Sun, 04 Jan 2009 21:05:14 +0100 Christian Heimes <lists(a)cheimes.de> wrote: > Philip Semanchuk schrieb: > > This works for me: > > PyModule_AddIntConstant(module, "O_CREAT", O_CREAT); > > > > I've had to learn a lot about writing extensions from looking at the > > Python source code. Lots of valuable tricks to be learned there. Thanks, that's perfect. I see it is documented, but I didn't know where to look. > This trick makes it even easier: > > #ifndef PyModule_AddIntMacro > #define PyModule_AddIntMacro(m, c) PyModule_AddIntConstant(m, #c, c) > #endif Good idea, but I'm a lot more experienced with C in general than in interfacing it with python, so I already thought of it :-). -- TH * http://www.realh.co.uk

1 0

Memory debugging tool for Python/C API?
by Robert Latest Jan. 5, 2009

Jan. 5, 2009

Hello, extending Python in C ist just the coolest thing since sliced bread (and I'm particularly happy because I really had started to miss C when I did more and more things in Python). I've got one question though. Tha C/API documentation is not quite clear (to me, anyway) on what happens exactly to ressources between the C/Python side. One example is this: I wrote a function that assembles a string into a dynamically-allocated buffer, then creates a PyString from it which it returns to the Python side: PyObject *dyn_string(void) { char *buffer = malloc(20); PyObject *pystr; strcpy(buffer, "Hello, World"); pystr = PyString_FromString(buffer); free(buffer); return pystr; } This works, but I'm not sure if PyString...() really makes a new copy of the data (ellowing me to use free()), or if this will segfault one day. OTOH I wouldn't know how to safely dispose of the string data otherwise. Another example (all on the C side of things) is a function where I build a dictionary from a set of keys, putting PyNone into each value (Py_INCREF()ing PyNone each time). At another point some of the values are replaced by other PyObjects. At first I used PyDECREF() on each value before setting the new value, but that botched up the dictionary beyond repair. Without the PyDECREF() calls everything worked fine. Now to my actual question: Is there some sort of debugging tool that I could use to analyze my code to see if everything gets properly allocated and deallocated and if the reference counting works right? Thanks, robert

2 1

Re: greenlets and how they can be used
by James Mills Jan. 5, 2009

Jan. 5, 2009

On Sun, Jan 4, 2009 at 4:52 AM, Benjamin Walkenhorst <krylon(a)gmx.net> wrote: > Back when I was still using Perl, there was - and still is, I guess - a really nice framework called POE, that allowed you to write event-driven state machines in a really easy and pleasant way. Under POE, EVERYTHING was an event. When writing a network server, each incoming client connection was an event, within a connection, each incoming piece of data was an event; when reading a file, each line fired an event (i.e. I/O was completely asynchronous); when querying a database, each result row would fire an event. What was even better, you could very easily plug GTK's or Tk's event loop into the whole mix and have GUI interactions fire events, too. > POE was one of the nicest software frameworks I have ever used, and I've been continuously frustrated by the lack of something like it in other languages such as Python or Ruby. It does exist :) It's called circuits. Or at least circuits is a framework that I develop and build which sounds very similar to POE in some ways :) cheers James

1 0

Re: Python3
by alexus Jan. 5, 2009

Jan. 5, 2009

On Jan 4, 4:46 pm, s...(a)pobox.com wrote: > alexus> enviroment: FreeBSD j.jothost.com 7.0-RELEASE-p7 FreeBSD 7.0-RELEASE- > alexus> p7 #6: Wed Dec 24 15:58:06 EST 2008 ale...@j.jothost.com:/usr/obj/ > alexus> usr/src/sys/GENERIC i386 > > alexus> I installed both of Python 2 and Python 3 via source code > alexus> (compile them myself) > > Where was Python 2 installed? /usr/bin or /usr/local/bin or somewhere else? > What was the --prefix arg to configure when building Python 3? > > S both of them were default --prefix, so I assume --prefix=/usr/local/ su-3.2# whereis python python: /usr/local/bin/python /usr/ports/lang/python su-3.2# /usr/local/bin/python --version Python 2.6.1 su-3.2# it's shows like 2.6.1 is there, yet when I ran "trac-admin", I get su-3.2# trac-admin Traceback (most recent call last): File "/usr/local/bin/trac-admin", line 5, in <module> from pkg_resources import load_entry_point ImportError: No module named pkg_resources su-3.2#

1 0

Package / Module Hierarchy question
by Torsten Mohr Jan. 5, 2009

Jan. 5, 2009

Hi, in a package i use these files: module (dir) __init__.py submodule __init__.py qwe.py qwe.py defines a class that derives from a class defined in submodule (and by that in submodule/__init__.py. Is it possible somehow to write in qwe.py to import submodule (though __init__.py is in the same directory as qwe.py ? I'd like to keep the tests for qwe.py within qwe.py, the code that i want to execute when i directly execute qwe.py and then: if __name__ == '__main__': some_test_code() Or do i need to write an external test code? Thanks for any hints, Torsten.

2 1

Re: Python3
by alexus Jan. 5, 2009

Jan. 5, 2009

On Jan 4, 4:23 pm, s...(a)pobox.com wrote: > alexus> I wanted to try out new Python 3 on my system, so I did "make > alexus> fullinstall" and now as promised it broke every single program > alexus> there is that runs on my system that depends on Python. > > alexus> is there a way to undo that? I've tried re-installing Python 2, > alexus> yet that didn't help me at all. > > The install targets for Python 3 explicitly don't create a symlink named > "python", so it's not obvious how you might have obliterated your Python 2 > installation. You didn't provide any information about your environment > (Windows? Linux? Mac? Was Python 2 provided by your OS vendor or > installed by you?) > > -- > Skip Montanaro - s...(a)pobox.com -http://smontanaro.dyndns.org/ sorry, for not providing all information at the first place, here it is: enviroment: FreeBSD j.jothost.com 7.0-RELEASE-p7 FreeBSD 7.0-RELEASE- p7 #6: Wed Dec 24 15:58:06 EST 2008 alexus@j.jothost.com:/usr/obj/ usr/src/sys/GENERIC i386 I installed both of Python 2 and Python 3 via source code (compile them myself)

2 1

Python3
by alexus Jan. 5, 2009

Jan. 5, 2009

I wanted to try out new Python 3 on my system, so I did "make fullinstall" and now as promised it broke every single program there is that runs on my system that depends on Python. is there a way to undo that? I've tried re-installing Python 2, yet that didn't help me at all.

2 1

Python training in Colorado, January 27-30
by Mark Lutz Jan. 5, 2009

Jan. 5, 2009

Python author and trainer Mark Lutz will be teaching a 4-day Python class on January 27-30, in Longmont, Colorado. This is a public training session open to individual enrollments, and covers the same topics and hands-on lab work as the onsite sessions that Mark teaches. The class provides an in-depth introduction to both Python and its common applications, and parallels the instructor's popular Python books. For more information on this session, please visit its web page: http://home.earthlink.net/~python-training/2009-public-classes.htm For additional background on the class itself, see our home page: http://home.earthlink.net/~python-training Thanks for your interest, --Python Training Services

2 1

How to declare python ints in C extensions?
by Tony Houghton Jan. 5, 2009

Jan. 5, 2009

I want to write python wrappers for the Linux DVB API. The underlying structures and constants may change from time to time, and some of the constants are generated from macros, so I think it would be better to write the module in C rather than just copying the constants into pure python code and using python's ioctl and struct modules. The trouble is I can't find out how to define a simple python int variable/constant in a C extension. The docs only seem to tell you how to define functions/methods and new types. For example, where the kernel header dvb/frontend.h defines: typedef enum fe_type { FE_QPSK, FE_QAM, FE_OFDM, FE_ATSC } fe_type_t; I want to make them available as if there was a python module dvb/frontend.py containing: FE_QPSK = 0 FE_QAM = 1 FE_OFDM = 2 FE_ATSC = 3 but in real life the module would be dvb/frontendmodule.c. -- TH * http://www.realh.co.uk

4 3

IDLE spinning beach ball on OS X 10.3.9 Panther
by kleefaj Jan. 5, 2009

Jan. 5, 2009

Greetings. I want to run IDLE on my iBook running Mac OS X 10.3.9 (Panther). Per the instructions on "Python on the Macintosh" [1], I downloaded and installed TclTkAqua [2], then downloaded and installed Universal- MacPython-2.4.3 [3]. Python launches in Terminal. The version shown is 2.4.3. When I launch IDLE (Applications/MacPython 2.4), a Console window and a *Python Shell* window open, and then I get the spinning beach ball. I have to Force Quit. Did I miss anything? How do I get this to work? Thanks, Jeff [1] http://www.python.org/download/mac/ [2] http://prdownloads.sourceforge.net/tcltkaqua/TclTkAqua-8.4.10.dmg?download [3] http://www.python.org/ftp/python/2.4.3/Universal-MacPython-2.4.3-2006-04-07…

2 1