How to pack and unpack using ctypes (Structure str)

by

The PythonInfo wiki has a solution for this.

FAQ: How do I copy bytes to Python from a ctypes.Structure?

def send(self):
    return buffer(self)[:]

FAQ: How do I copy bytes to a ctypes.Structure from Python?

def receiveSome(self, bytes):
    fit = min(len(bytes), ctypes.sizeof(self))
    ctypes.memmove(ctypes.addressof(self), bytes, fit)

Their send is the (more-or-less) equivalent of pack, and receiveSome is sort of a pack_into. If you have a “safe” situation where you’re unpacking into a struct of the same type as the original, you can one-line it like memmove(addressof(y), buffer(x)[:], sizeof(y)) to copy x into y. Of course, you’ll probably have a variable as the second argument, rather than a literal packing of x.

More Related Contents:

  1. Python & Ctypes: Passing a struct to a function as a pointer to get back data
  2. C function called from Python via ctypes returns incorrect value
  3. Python Ctypes – loading dll throws OSError: [WinError 193] %1 is not a valid Win32 application
  4. C-like structures in Python
  5. Python ctypes cdll.LoadLibrary, instantiate an object, execute its method, private variable address truncated
  6. How do I prevent a C shared library to print on stdout in python?
  7. python ctypes issue on different OSes
  8. WindowsError: [Error 126] The specified module could not be found
  9. Getting data from ctypes array into numpy
  10. How do I convert a Python list into a C array by using ctypes?
  11. Changing LD_LIBRARY_PATH at runtime for ctypes
  12. How can I unload a DLL using ctypes in Python?
  13. C DLL loads in C++ program, not in python Ctypes
  14. ctypes – Beginner
  15. What files are required for Py_Initialize to run?
  16. How to use IFileOperation from ctypes
  17. packing and unpacking variable length array/string using the struct module in python
  18. python ctype recursive structures
  19. Why won’t this ctypes code work with Python 3.3 but will work with Python 2.7?
  20. How do I set the desktop background in python? (windows)
  21. Can’t import dll module in Python
  22. Maximum and minimum value of C types integers from Python
  23. Can I access ImageMagick API with Python?
  24. How to pass a 2d array from Python to C?
  25. ctypes error: libdc1394 error: Failed to initialize libdc1394
  26. Python and ctypes: how to correctly pass “pointer-to-pointer” into DLL?
  27. Sorting list of string with specific locale in python
  28. Using Python class as a data container [closed]
  29. WindowsError: [Error 126] when loading a DLL with ctypes
  30. stdout redirection with ctypes

Leave a Comment