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Can't import .so using ctypes in Python

Problem
I am trying to link C++ with python, so I compiled a .so file via g++ (the MinGW version, so I believe it should be able to run on Windows) and then in python:
import ctypes
lib = ctypes.cdll.LoadLibrary("support.so")
I get the Error:
FileNotFoundError: Could not find module 'support.so' (or one of its dependencies). Try using the full path with constructor syntax.
I tried using the full path and using os.add_dll_directory(), but didn't help.
Environment
Python 3.8 / 3.9 both not working
The .so file is created by myself, it is compiled via g++.
I encourtered this problem first on Windows 11, and solved it by changing the winmode in ctypes.__init__() by the help of this answer https://stackoverflow.com/a/64472088/9249608.
However, when I copy this program and the .so file to another computer with Window 10, I cannot solve this problem by any of the above methods. I even tried adding the folder to the PATH or copying this .so file to the python folder, but it still produces the error.
Is there any way that I can know exactly which paths are being searched? I see that there are many searching modes in ctypes.__init__() but I don't know how to output the corresponding searching paths.

pySide: ExtensionLoader_Pyside_QtGUI.py specified module could not be found

I'm using CXFreeze with PySide (QT). I get an error:
cx_Freeze: Python error in main script.
myscript.py line 33, in
File ExtensionLoader_Pyside_QtGUI.py, line 11, in
Import Error: DLL load failed: The specified module could not be found
When running a fresh install of Windows server 2008.
I'm running the frozen EXE package (with the folder). It seems to work on my own system and other systems. What might be the issue?
After reading, online, I tried to replace the Qt4Gui file, but this didn't solve the issue.
Python version is 2.7

Based on your Import Error: DLL load failed it is most likely an installation issue causing the missing DLL. To figure our exactly which DLL you are missing, use http://www.dependencywalker.com/ Run the .exe and open the .pyd file for File ExtensionLoader_Pyside_QtGUI.py and it will show you exactly which DLL's are missing and more importantly the locations where they should be. You can probably then track down the missing DLL online.

there are known issues with pyside 1.2.0 and cxFreeze. All should be fixed in development version (available on git repo). Please build the PySide from latest sources yourself or wait for PySide version 1.2.1. Build instructions are here [1].
[1] https://github.com/PySide/pyside-setup#building-pyside-on-a-windows-system

I used Py2exe instead of CXFreeze and it worked perfectly.
Also, apparently Python requires the MS Visual C++ Dependency Files:
http://www.microsoft.com/en-us/download/details.aspx?id=29
So any bundling needs that as well, if it's a fresh install. (Although I think they are now bundled with newer Windows versions.)
Other Notes:
In my experience, sometimes you should try CXFreeze, Py2EXE and PyInstaller quickly and see if one works best. As ideal as CXFreeze is re: cross platform, it just isn't going to happen perfectly.
Also, while I don't know if this was a factor, I set up a Windows 2000 Pro virtual machine and ran Py2exe on that. That was to ensure compatibility for all older Windows versions, and seemed to work well. (NOTE: Many things won't even run on Win2000 anymore so be careful that your other tools and libraries will run on it.)
Finally, be extra careful to match the bit level (32 vs 64) of all your libraries, and your Python install itself. If you have 32-bit python, ensure that your PySide, CXFreeze and any other libraries you use are 32-bit. (Or 64-bit if you're using 64-bit python.)

python, unable to make executable from script when I use scipy

I have a python application and I want to extract the executable. I have used py2exe with no problem in other scripts. But in this one I get errors that I think have to do with the fact that I import and use scipy.
My code runs fine in eclipse. Trying to make the procedure with scipy at first I got 3 dlls missing ("libmmd.dll","MSVCP90.dll","libifcoremd.dll"). At first I exluded these from setup.py and the .exe file was made but it did not run. After that I downloaded the dll files (also deleted the exclusion of setup.py) and added them in "C:\Python27\DLLs" and also "C:\Windows\System32" and "C:\Windows\SysWOW64" (I have 64 bit windows7). Again the exe is created in the folder dist, but trying to run it I get this:
http://imageshack.us/photo/my-images/145/py2exe.png/
Then I tried to do it with cx_Freeze. Again the .exe file was created but I get this error:
http://img521.imageshack.us/img521/3843/cxfreeze.png
So I suppose it has nothing to do with py2exe or cx_Freeze, but with the fact that scipy needs some dependencies that for some reason work in eclipse, but not when I make the executable.
Has anybody faced this problem? Any ideas on what I should do?
Thank you in advance!
EDIT: I did it with pyinstaller-2.0. It did not run at first. Then I added the DLLs to the folder, after that I added numpy and scipy to the folder and finally after an error message I added kdtree.py to the folder. I was thrilled to see that it runned! But then dissapointed again cause it runs ONLY in my pc (some useful .exe there)! I added the folder it to a dropbox folder, from where it runs in me with no problem but not for others. The error in other machines I tried is:
importError: DLL load failed: %1 is not a valid Win32 application

You could try putting the DLL files directly next to your executable. Also my py2exe gives some information about possible binary files that you might need to distribute with your application:
*** binary dependencies ***
Your executable(s) also depend on these dlls which are not included,
you may or may not need to distribute them.
Make sure you have the license if you distribute any of them, and
make sure you don't distribute files belonging to the operating system.
//Snip list of paths to dlls

Cx_Freeze DLL load failed

I have been trying to use cx_freeze for some time now, and yet the same error always occurs
import cx_Freeze.util
ImportError: DLL load failed: %1 is not a valid win32 application
I have tried with both 32 and 64 bit, and have tried both setup.py and cxfreeze.bat
what I am asking is, how do I make it work?

I have had the same problem and this was my solution.
I am using Python 3.2 for windows 64 bit and my library installations were all for 64 bit, including cx_freeze. When I tried to "freeze" a program that imported the PyQt4 package, I got the error:
ImportError: DLL load failed: %1 is not a valid win32 application
In my case, the problem was that the cxfreeze script was copying two DLL files (QtCore4.dll and QtGui4.dll) from my MATLAB installation, rather than from my Python installation. The MATLAB DLLs were 32 bit whereas the Python DLLs were the required 64 bit files.
Read the messages displayed when you run the cxfreeze script to build your exe files. The last few messages should be "copying ...dll-> ....dll". Check the filenames and make sure that all the files are actually being copied from your Python installation and not some other program.
If they are being copied from elsewhere (as in my case) you can simply copy them over yourself after the build. Otherwise, you will have to change your path not to include the folder containing the 32 bit DLLs from whatever program they belong.

How to use OpenCV in Python?

I have just installed OpenCV on my Windows 7 machine. As a result, I get a new directory:
C:\OpenCV2.2\Python2.7\Lib\site-packages
In this directory, I have two files: cv.lib and cv.pyd.
Then I try to use the opencv from Python. I do the following:
import sys
sys.path.append('C:\OpenCV2.2\Python2.7\Lib\site-packages')
import cv
As a result I get the following error message:
File "<stdin>", line 1, in <module>
ImportError: DLL load failed: The specified module could not be found.
What am I doing wrong?
ADDED
As it was recommended here, I have copied content of C:\OpenCV2.0\Python2.6\Lib\site-packages to the C:\Python26\Lib\site-packages. It did not help.
ADDED 2
My environment variables have the following values:
Path=C:\Program Files\MiKTex\miktex\bin;C:\OpenCV2.2\bin;C:\Python26;
PYTHONPATH=C:\OpenCV2.2\Python2.7\Lib\site-packages
Do I need to change something? Do I need to add something?
ADDED 3
I think my question is general: How to use a library? Probably I need to find a *.ddl file somewhere? Then I need to use the name of the directory containing this file as a value to some environment variables? Or maybe I need to use sys.addpath? I also need to know how the way to call the library is related to the name of the file that contains the library.
ADDED 4
It is interesting that when I type import cv, I get:
ImportError: DLL load failed: The specified module could not be found.
But when I type import opencv I get:
ImportError: No module named opencv
ADDED 5
It has been suggested that I usthe e inconsistent version of python. In more details, OpenCV tries to use Python2.7 and I had Python2.6. So, I have installed Python 2.7. It makes difference. Now I do not have the old error message, but I have a new one:
ImportError: numpy.core.multiarray failed to import
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: numpy.core.multiarray failed to import
ADDED 6
I have managed to resolve the problem by installing numpy. It took some time because I did not realized that there are different numpy installer corresponding to different versions of Python. Some details can be found in my answer to my own question (see bellow).

The problem was resolved. The following steps has been done:
A new version of python (version 2.7) has been installed.
After that I still was unable to run OpenCV because I had some problems with the numpy library.
I tired to install numpy but the installer did not see my new version of the Python.
I deleted the old version of Python as well as links to the old version in the Path system vatriable.
After that numpy installer was not able to finish the installation.
I have realized that I need to run another numpy installer that is associated with the Python 2.7. It can be found here.
Finally everything worked. I was able to "import cv".

I suspect you have the same problem I've run into. If you have a 64-bit version of Python, it cannot load 32-bit DLLs. OpenCV currently only ships 32-bit binaries. If you want 64-bit .pyd and .dll files, you have to compile them yourself. There are some instructions on the OpenCV Wiki, but it's not for the faint of heart. Expect to have a substantial time investment.
The easiest solution is to:
Uninstall 64-bit Python
Install a 32-bit distribution.
The PythonXY distribution includes pyopencv -- a good set of OpenCV hooks. The only limitation is that it's 32-bit, so don't make plans to process gigapixel astronomy data with it! ;)
If you must have the 64-bit version, follow these instructions to get it OpenCV to compile with Visual Studio 2010. There's a discussion on stackoverflow that describes building 64-bit apps with VC Express.
EDIT: OpenCV now ships with 64-bit Python binaries. The .dll files need to go somewhere in your path (I put them in the scripts folder), and the .pyd files go in your site-packages directory.

I had trouble interfacing OpenCV with Python, and I was looking all over the place for help. Here's what worked for me. I basically followed this post: http://opencvpython.blogspot.com/2012/05/install-opencv-in-windows-for-python.html. After downloading and extracting OpenCV 2.4.6, you basically get a folder called "opencv" with a bunch of stuff in it. Navigate to build->python->2.7. Inside, there is only one file called "cv2.pyd". I copied this file and pasted it in "python-2.7.5\Lib\site-packages". I'm actually using the Spyder IDE, and it works fine. In the python interpreter, typing in "import cv" worked for me.

Maybe you should edit your environment variable
right click on the "My Computer" or something like this, click on properties.
In the properties window click on the Advanced tab.
Then, the environment variables button.
Change the path.