Calling Python script from C++ and using its output

by

Here is a solution to embed the execution of your python module from within your C++ application. It’s not better or worst than forking/executing your python script through a system call, it just is a different way to do it. Whether it is best or not depend on your context and usage.

Some time ago I have coded a way to load python modules as plugins to a C++ application, here’s the interesting part.

Basically, you need to #include <Python.h>, then Py_Initialize() to start your python interpreter.

Then you do import sys, using : PyRun_SimpleString("import sys");, and you can load your plugin by doing PyRun_SimpleString('sys.path.append("path/to/my/module/")').

To exchange values between C++ and Python, things get harder, you have to to transform all your C++ objects into python objects (starting line 69 in my script).

Then you can call your function using PyObject_Call_Object(...), using all the python objects you created as arguments.

You get the return value, and transforms all those values in C++ objects. And don’t forget the memory management in all that!

To end your python interpreter, a simple call to Py_Finalize().

It really looks harder than it is really, but you have to be really careful doing this, because it could lead to leaks, security issues etc..

More Related Contents:

  1. How to match a string to pattern “Foo-Bar”, where Bar can be any element of a list? [closed]
  2. Searching for IP addresses in a file
  3. Swapping variable places inside if throws an error
  4. How to remove English words from a file containing Dari words?
  5. How can I read inputs as numbers?
  6. Behavior of exec function in Python 2 and Python 3
  7. Why is a list comprehension so much faster than appending to a list?
  8. How to print a string at a fixed width?
  9. How to use pip with Python 3.x alongside Python 2.x
  10. Why is parenthesis in print voluntary in Python 2.7?
  11. How can I make a for-loop pyramid more concise in Python? [duplicate]
  12. Backporting Python 3 open(encoding=”utf-8″) to Python 2
  13. Getting only element from a single-element list in Python?
  14. Why does this not work as an array membership test? [duplicate]
  15. Accessing attributes on literals work on all types, but not `int`; why? [duplicate]
  16. Using multiple Python engines (32Bit/64bit and 2.7/3.5)
  17. Accessing attributes on literals work on all types, but not `int`; why? [duplicate]
  18. How to print a list with integers without the brackets, commas and no quotes? [duplicate]
  19. Python regex for unicode capitalized words
  20. How to create a Python dictionary with double quotes as default quote format?
  21. PyOpenGL glutInit NullFunctionError
  22. How to apply a function to each sublist of a list in python?
  23. Python 3 urllib produces TypeError: POST data should be bytes or an iterable of bytes. It cannot be of type str
  24. How to read the last line of a file in Python? [duplicate]
  25. Multiple keys per value
  26. WinError 2 The system cannot find the file specified (Python)
  27. Is there a reason Python 3 enumerates slower than Python 2?
  28. What is absolute import in python?
  29. ‘is’ operator behaves unexpectedly with floats
  30. Converting string to tuple without splitting characters

Leave a Comment