[python] 最簡單的方法呼叫 pyx code 使用 C

How to invoke pyx code from C

井民全, Jing, mqjing@gmail.com

已經知道如果程式碼使用 cython language 撰寫, 將來的執行速度會是原來 python 的 10 倍.
所以我來 go through 了一次, 如何從 C 來呼叫 pyx module 的 code.

內容包含:

• 最簡單的 pyx code
• 如何自動轉換 pyx code 到 C 產生 object files
• 最簡單的呼叫 pyx module 範例 from C

Enjoy

Jing.

Pyx Code

cdef public void my_python_module(): print('1234')

Quick

# transfer and build cython my_python.pyx gcc my_python.c -o my_python.o -shared -pthread -fPIC -fwrapv -O2 -Wall -fno-strict-aliasing -I/usr/include/python3.5 # usage ----------- main.c ------------- #include #include "my_python.h" int main() { Py_Initialize(); PyInit_my_python(); // ---- init the python module my_python_module(); // ---- call my python module Py_Finalize(); return 0; } --------------------------------------- gcc main.c -ldl my_python.o -I/usr/include/python3.5 -L/usr/lib/python3.5/config-3.5m-x86_64-linux-gnu -lpython3.5 # run ./a.out

Detail

Transfer the pyx code to C module

Step 1: Generate the C code

cython my_python.pyx   

Or python setup.py build_ext --inplace

Result

Step 2: Build the object file

gcc my_python.c -o my_python.o  -shared -pthread -fPIC -fwrapv -O2 -Wall -fno-strict-aliasing  -I/usr/include/python3.5

Result

Usage

main.c

#include #include "my_python.h" int main() {  Py_Initialize();  PyInit_my_python();   // <---- init="" module="" python="" span="" the="">  my_python_module();   // <---- call="" module="" my="" python="" span="">  Py_Finalize();  return 0; }

Build and Run

Step 1: build the source code

gcc main.c -ldl my_python.o -I/usr/include/python3.5 -L/usr/lib/python3.5/config-3.5m-x86_64-linux-gnu -lpython3.5

Step 2: Setup the shared library path, LD_LIBRARY_PATH

LD_LIBRARY_PATH=.

export LD_LIBRARY_PATH

Step 3: Run

./a.out