Python is an interpreted, general-purpose high-level programming language whose design philosophy emphasizes code readability.
Questions tagged [python-extensions]
323 questions
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0 answers
Passing double arrays from Python to C++ extensions
I understand a basic C++ function wrapped for Python looks like this:
int square(int n)
{
return n*n;
}
static PyObject* square_wrapper(PyObject* self, PyObject* args)
{
int n = 0;
if(!PyArg_ParseTuple(args, "i", &n))
return…
Aidan Lethaby
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1 answer
Passing byte string from Python to C
I am writing a python extension in C and I am trying to pass a bytes object to my function. Obviously the 's' token is for strings; I have tried 'O', 'N', and a few others with no luck. Is there a token I can use to parse a bytes object? If not is…
Daniel
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1
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1 answer
Need guidance regarding reference counting
I'm chasing a memory leak that seems to come from a long-running process which contains a C extension that I wrote. I've been poring over the code and the Extensions docs and I'm sure it's correct but I'd like to make sure regarding the reference…
musbur
- 567
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0 answers
"corrupted double-linked list" after C++ python extension program terminates
I am developing a program that extends python with C++ code, and it looks like I'm missing something in initialization or cleanup. The symptom is that when the program terminates it prints out something like this:
*** glibc detected *** ...…
Michael
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1 answer
How would I create a Python library that is extended by using C?
My goal is to create a Python library that I can import into any of my projects, and I wish to have the library made faster by the use of the C language (similar to how NumPy works).
However, after following many different tutorials and videos, I…
Pencilcaseman
- 360
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1
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1 answer
Why does PyArg_ParseTuple always return false?
My PyFLoat_ParseTuple call always return false, with correct call from python side.
I am working on wrapping my C++ for Python and using python extension.
I had a successful project, and generating the current one based on that.
I always had a crash…
Charlie
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- 4
1
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1 answer
Can't correctly convert Numpy array to c array for Python Extension (c++)
I'm developing a Python extension in c++. I'm am really rusty in c++ however and don't have the necessary experience to figure this out it seems. I'm trying to read in numpy arrays, do the calculations I want to do and then return a numpy array. The…
Mineral
- 197
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1
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1 answer
C code crashes attempting Python remote procedure call via xmlrpc
I'm trying to create C code that creates an Python xmlrpc client and calls methods on the xmlrpc server (I'm thinking of using this as IPC for a hook DLL).
Here's the code ... I'm not going to layer in reference counting until it works.
#include…
MikeRand
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1
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1 answer
Using Python object exported from DLL in an exe
I have a two-part event generator:
pyglobalexe (a stub to simulate events):
#pragma comment(lib, "pyglobalextension.lib")
#include
__declspec(dllimport) PyObject* PyInit_pyglobalextension;
__declspec(dllimport) PyObject*…
MikeRand
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1
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0 answers
How to free memory early for a PyObject?
I have a large (numpy ndarray) object whose memory I want to free as soon as I am finished with it in my Python extension (or I will quickly run out of memory). How can I safely do this?
It seems that in Python, something like del arr followed by…
Zach Boyd
- 419
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1
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2 answers
Creating .so file using ctypes when opencv is included in C++ code
I am trying to create .so file of a c++ file(twocams.cpp) which includes main() and another C++ file (say abc.h). abc.c includes opencv. while creating an object using ctypes,
g++ -fPIC -shared twocams.cpp -o twocams.so
Test =…
Arun Sharma
- 29
- 8
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2 answers
Python extension in C - Metaclass
I have the following python code:
class Meta(type):
def __call__(cls, *args, **kwargs):
obj = type.__call__(cls, *args, **kwargs)
# Only do checks for subclasses
if cls.__name__ == 'Parent':
return obj
…
Nelson
- 922
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1
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0 answers
Very different size of *.so and *.pyd, why?
I managed to build *.pyd library. Sweat, blood, tears and gore aside, it turned out to be about 4 (four) times smaller than the corresponding *.so library.
While the code seems to work, I cannot help but to wonder why the difference is so huge. Is…
wvxvw
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1
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0 answers
Python extension build chokes on `std::unique_ptr` on Mac
I have a toy project that's implemented as a C++ library and exposed to Python using a Cython wrapper. After not touching the project for a few months, I tried to build it from scratch today and got the following error.
gcc -Wno-unused-result…
Daniel Standage
- 8,136
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1
vote
1 answer
Trouble with DateTime object methods in C++ extension
I'm working on a C++ extension for Python 3 and trying to pass a DateTime object to my function. the PyDateTime_Check function seems to work and returns true, but when I try to get the year from the DateTime object it returns 65535. I'm passing…
Lucian
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