python-c-extension

This question already has answers here : PyEval_InitThreads in Python 3: How/when to call it? (the saga continues ad nauseam) (7 answers) Closed 6 years ago . I'm a bit confused about when I'm supposed to call PyEval_InitThreads . In general, I understand that PyEval_InitThreads must be called whenever a non-Python thread (i.e. a thread that is spawned within an extension module) is used. However, I'm confused if PyEval_InitThreads is for C programs which embed the Python interpreter, or Python programs which import C-extension modules, or both. So, if I write a C extension module that will

I've read the documentation for the Python C-API, and even written a few extension modules. However, I'm still a bit unclear on the exact semantics when it comes to returning Python objects from a C function. The limited examples in the Python docs usually show a C function which returns the result of Py_BuildValue . Now, Py_BuildValue returns a New Reference , and transfers ownership of this reference over to the interpreter. So, can I extrapolate from this that it is a general rule that any object returned to Python must be a new reference , and that returning an object from a C function is

I'm reading the documentation for Memory Management in Python C extensions , and as far as I can tell, there doesn't really seem to be much reason to use malloc rather than PyMem_Malloc . Say I want to allocate an array that isn't to be exposed to Python source code and will be stored in an object that will be garbage collected. Is there any reason to use malloc ? EDIT : Mixed PyMem_Malloc and PyObject_Malloc corrections; they are two different calls. Without the PYMALLOC_DEBUG macro activated, PyMem_Malloc is an alias of libc's malloc() , having one special case: calling PyMem_Malloc to

I've am learning about Python-C extensions and am puzzled as to why methods that use keyword arguments must be cast to PyCFunctions. My understanding of a PyCFunction is that it takes two pointers to PyObjects and returns a single pointer to a PyObject - e.g. PyObject* myFunc(PyObject* self, PyObject* args) If I'm going to use a function that uses keyword arguments, then this function will take three pointers to PyObjects and returns a single pointer to a PyObject - e.g. PyObject* myFunc(PyObject* self, PyObject* args, PyObject* keywordArgs) However, when I create the module functions array

If I'm understanding correctly, PyMODINIT_FUNC in Python 2.X has been replaced by PyModule_Create in Python3.X Both return PyObject* , however, in Python 3.X, the module's initialization function MUST return the PyObject* to the module - i.e. PyMODINIT_FUNC PyInit_spam(void) { return PyModule_Create(&spammodule); } whereas in Python2.X, this is not necessary - i.e. PyMODINIT_FUNC initspam(void) { (void) Py_InitModule("spam", SpamMethods); } So, my sanity checking questions are: Is my understanding correct? Why was this change made? Right now, I'm only experimenting with very simple cases of C