capi-sig December 2012

capi-sig@python.org

7 participants
23 discussions

Re: [capi-sig] Does Py_False or Py_True need de-referencing if used in a PyObject_Compare?

by Stefan Behnel

Robert Steckroth, 13.12.2012 17:57: > Well, from what I have gathered, the reference count does not need to be > maintain as far as PyBool objects go. They are like any other object, i.e. they need reference counting. > It seem to be fine even if the object is set from a argument. Hmmm... That's a different case. As long as you are sure that someone (better you) owns a reference to the object that you pass as argument, you don't need to increase its refcount just for the call. That's easy to get wrong, though. >> Does the below statement have a memory leak? >> >> if ( PyObject_Compare(update_var, Py_False) Why should it? >> Do I need to assign the Py_False first and DECREF it, or is the above >> snippet ok alone. I keep being surprised by what some people take their fun in programming from. Good to see that you're getting actual functionality done regardless. Stefan

7 years, 7 months

Re: [capi-sig] Does Py_False or Py_True need de-referencing if used in a PyObject_Compare?

by Robert Steckroth

Well, from what I have gathered, the reference count does not need to be maintain as far as PyBool objects go. It seem to be fine even if the object is set from a argument. Hmmm... On Thu, Dec 13, 2012 at 11:21 AM, Robert Steckroth < robertsteckroth(a)gmail.com> wrote: > Does the below statement have a memory leak? > > if ( PyObject_Compare(update_var, Py_False) > > Do I need to assign the Py_False first and DECREF it, or is the above > snippet ok alone. > > -- > Bust0ut, Surgemcgee: Systems Engineer --- > surgemcgee.com > Django_Teamplate3d > -- Bust0ut, Surgemcgee: Systems Engineer --- surgemcgee.com Django_Teamplate3d

7 years, 7 months

Does Py_False or Py_True need de-referencing if used in a PyObject_Compare?

by Robert Steckroth

Does the below statement have a memory leak? if ( PyObject_Compare(update_var, Py_False) Do I need to assign the Py_False first and DECREF it, or is the above snippet ok alone. -- Bust0ut, Surgemcgee: Systems Engineer --- surgemcgee.com Django_Teamplate3d

7 years, 7 months

How do I get the Objects to clean up after a python script exits?

by Robert Steckroth

When I test my module in the interpreter it automatically cleans up any created objects. This is a very nice feature for my module and I would like to use it. How do I go about getting my scripts to send an exit cleanup single? -- Bust0ut, Surgemcgee: Systems Engineer --- surgemcgee.com Django_Teamplate3d

7 years, 7 months

Re: [capi-sig] Open sourced the Python PySurface Module!

by Hrvoje Niksic

Robert Steckroth <robertsteckroth(a)gmail.com> writes: > Hello Gang, I have open-sourced the PySurface module and started the > documentation. I know there is some novel ideas in there for anyone in > this field, so check it out. I can't wait to slap this one into my > resume! Also, any constructive criticism is welcome as this project a > large cookie. Congratulations! However, the python mailing list/newsgroup might be a better place for the announcement, as this list has a fairly narrow audience. You might also want to put up the project on PyPI, so it gets some attention.

7 years, 7 months

Open sourced the Python PySurface Module!

by Robert Steckroth

Hello Gang, I have open-sourced the PySurface module and started the documentation. I know there is some novel ideas in there for anyone in this field, so check it out. I can't wait to slap this one into my resume! Also, any constructive criticism is welcome as this project a large cookie. I have not uploaded the Docs to ReadTheDocs.org yet, so you can scope out my in-house design and get the repository here --> www.surgemcgee.com Robert Steckroth -- Bust0ut, Surgemcgee: Systems Engineer --- surgemcgee.com Django_Teamplate3d

7 years, 7 months

Re: [capi-sig] Does PyObject_SetAttrString am PyArg_Parse steal an object reference?

by Hrvoje Niksic

Robert Steckroth <robertsteckroth(a)gmail.com> writes: > In the below example, is there an extra reference to the align object > when the Py_RETURN_NONE IS hit? There is. Since PyObject_SetAttrString doesn't steal the reference count to its argument, the Py_XINCREF is unnecessary. Also, I'd use Py_INCREF there, since you already aren't entering the if-clause if align is NULL. > Also, why do I have to Py_INCREF(s_obj)? You don't. PyArg_ParseTupleAndKeywords doesn't increase reference count of its arguments, and neither should the code calling it -- it is the responsibility of the caller to provide arguments that it either owns or are globally available (Py_None, type objects). > If I do not, I end up with crashes. Is this a bug? It's most likely a bug somewhere else in your code or an extension you're using that gets hidden by the extra incref. This can sometimes happen in Python/C; the correct solution is to remove the extraneous incref and carefully inspect the rest of your code for incorrect reference count handling.

7 years, 7 months

Does PyObject_SetAttrString am PyArg_Parse steal an object reference?

by Robert Steckroth

In the below example, is there an extra reference to the align object when the Py_RETURN_NONE IS hit? Also, why do I have to Py_INCREF(s_obj)? If I do not, I end up with crashes. Is this a bug? PyObject *s_obj=NULL, *align=NULL; if ( ! PyArg_ParseTupleAndKeywords(args, kwds, "|OO", kwlist, &s_obj, &align) ) return NULL; if ( s_obj ) Py_XINCREF(s_obj); if ( align ) { Py_XINCREF(align); PyObject_SetAttrString(s_obj, "align", align); } Py_RETURN_NONE; } -- Bust0ut, Surgemcgee: Systems Engineer --- surgemcgee.com Django_Teamplate3d

7 years, 7 months

Re: [capi-sig] How to retrieve an objects method or attribute doc string?

by Hrvoje Niksic

Robert Steckroth <robertsteckroth(a)gmail.com> writes: > I have an Python Object with a type PySurface_Type. The Object > has a method called Properties like so -> > > {"Properties", (PyCFunction)Surface_set_properties, METH_VARARGS| > METH_KEYWORDS, > "Set the surface properties as a list of integers or keywords, e.g. > set_properties(x=[int][PyList[int, ...], y=int, width=int, height=int). > Note: the Python list must be the first argument or x=PyList[int, ...] > "}, > > How can I get the doc string from this method? I would like to print this > in an error message. The docstring is available as the __doc__ attribute of the surface.Properties object ("surface" being the Python name of PySurface_Type). In Python one would access it as surface.Properties.__doc__, which would translate to Python/C as: const char *surface_props_doc_string() { PyObject *propdeco, *doc; const char *doc_str; propdeco = PyObject_GetAttrString((PyObject *) PySurface_Type, "Properties"); if (!propdeco) return NULL; doc = PyObject_GetAttrString(propdeco, "__doc__"); Py_DECREF(propdeco); if (!doc) return NULL; doc_str = PyString_AsString(doc); Py_DECREF(doc); return doc_str; }

7 years, 7 months

How to retrieve an objects method or attribute doc string?

by Robert Steckroth

I have an Python Object with a type PySurface_Type. The Object has a method called Properties like so -> {"Properties", (PyCFunction)Surface_set_properties, METH_VARARGS| METH_KEYWORDS, "Set the surface properties as a list of integers or keywords, e.g. set_properties(x=[int][PyList[int, ...], y=int, width=int, height=int). Note: the Python list must be the first argument or x=PyList[int, ...] "}, How can I get the doc string from this method? I would like to print this in an error message. Is it possible to get the Member doc string as well? -- Bust0ut, Surgemcgee: Systems Engineer --- surgemcgee.com Django_Teamplate3d

7 years, 7 months

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capi-sig December 2012