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Using embedded python, loading a *.pyd outside of DLLs directory fails

I have a C++ application (X-Plane) for which there is a plugin which permits the use of python scripts (XPPython3 plugin). The plugin is written in C, using python CAPI, and works great, allowing me to write python scripts which get executed within the C++ application.
On Windows 10, I want to extend my python features by importing imgui. I have a python cython-built pyd file (_imgui.cp39-win_amd64.pyd).
If I place the pyd file in C\Program Files\Python39\DLLs, it works as expected: C++ application calls CAPI to python, which loads script which imports and executes imgui code.
If I place the pyd file anywhere else, embedded python either reports "module not found" -- if the pyd isn't on sys.path(), or if it is on sys.path():
ImportError: DLL load failed while importing _imgui: The parameter is incorrect.'
Changes using: os.add_dll_directory(r'D:\somewhere\else')
Does not effect whether the module is found or not, nor does it change the 'parameter incorrect' error. (see https://bugs.python.org/issue36085 for details on this change. -- my guess is add_dll_directory changes lookup for DLLs, but not for pyd?) sys.path appears to be used for locating pyd.
Yes, the pyd is compiled with python3.9: I've compiled it both with mingw and with visual studio toolchains, in case that might be a difference.
For fun, I moved python-standard _zoneinfo.pyd from Python39\DLLs and it fails in the same way in embedded python: "The parameter is incorrect". So, that would appear to rule out my specific pyd file.
The key question is/are:
Other than placing a pyd file under PythonXX\DLLs, is there a way to load a PYD in an embedded python implementation? (I want to avoid having to tell users to move my pyd file into the Python39\DLLs directory... because they'll forget.)
Note that using IDLE or python.exe, I can load pyds without error -- anywhere on sys.path -- so they don't have to be under Python39\DLLs. It's only when trying to load from embedded python that the "Parameter is incorrect" appears. And of course, this works flawlessly on Mac.
(Bonus question: what parameter? It appears to be python passing through a windows error.)

There seems to be a simple answer, though I suspect it's better characterized as a python bug.
There is nothing magical about Python39\DLLs directory.
The problem is using absolute vs relative paths in sys.path.
Python can find modules using absolute or relative paths. So if zippy.py is in folder foobar,
sys.path.append('foobar')
import zippy
# Success
Python and find, BUT NOT LOAD pyd files using relative paths. For example, move _zoneinfo.pyd from PythonXX\LDDs to foobar
sys.path.append('foobar')
import _zoneinfo
# ImportError: DLL load failed while importing _zoneinfo: The parameter is incorrect.'
Instead, use absolute path, and it will find and load PYD:
sys.path.append(r'c:\MyTest\foobar')
import _zoneinfo
# Success

So, there is actually a way to do this—that is, ship your application with the desired libraries. The solution is to use an embedded distribution and ship this with your application. You can find the correct distribution on the official Python download page corresponding to your desired version (here's the link to the lastest 3.9 release which seems to be what you're using: https://www.python.org/downloads/release/python-392/). Look for the Windows Embeddable Package.
You can then simply drop in your .pyd file alongside the standard library files (note that if your third-party library is dependent on any other libraries, you will have to include them, as well). Shipping your application with an embeddable distribution should not only solve your current issue, but will also mean that your application will work regardless of which version of Python a user has installed (or without having Python installed at all).

Python/C++ wrapper Using external dll with Pybind11

Python version: 3.8.1
Spyder version: 3.3.6
Qt version: 5.12.9
Wrapper: develop using PyBind11
I am wrapping a dll develop in C++ which use Qt dlls to be used with Python. I wrote the wrapper with Visual Studio 2019 using the compiler MSVC (as my dll is compiled with MSVC). After generating the solution in VS2019 I obtain a .pyd file which can be import with python.
It works good when I use python on line command:
Start cmd.exe
$python
import MyLibName
I can use the functions/classes ...
But if I try with Spyder, I get the following error:
ImportError: DLL load failed while importing PyStack: The specified module could not be found..
So here are my questions :
Is there a way to get more information about ImportError like the name of the missing dll or something?
I don't understand why the issue only happen with spyder. I tried with IPython Qt Console and it work. Does spyder use a embeded python version or something ?
I don't fully understand how dll shall be managed, I mean shall I provide dll like libGLESV2.dll with the .pyd or just give a path where to find it ?
Thank you in advance.

My guess
I think I find out which part of Qt/python is producing this issue, but I still don't know how to solve it.
My dll use signals/slots which need an event loop to be performed. If an event loop is already running the dll will try to use it, if the loop version (ex : PyQt5==5.14.1) isn’t the same as mine (ex Qt==5.15.1) import will be impossible.
Note that the reverse is true, if I run my dll an then try to start a loop with %gui qt the command will throw an error.
How to reproduce the issue :
Compile a Qt project available here.
Copy the output dll in the folder PyMyStack/dependencies of the VS Project (available here)
Compile the VS project.
Open an IPython console (without using qt has event loop)
Import the module created with VS (Import PyMyStack)
Run the magic command %gui qt
Last command shall print : ERROR:root:DLL load failed while importing QtSvg: The specified procedure could not be found.
How to hide/solve the problem:
Disclaimer : The solutions presented here are surely not the best, if you know a better one please share it ☺
If you just want to import your lib in Spyder, you can use another event loop. Here are the steps to change this:
In Spyder menus go to Tools→Preferences
Select “IPython console”
Go to “Graphics” tab and change the backend combo box to any other values than Qt or Automatic
If you want to use Qt event loop you will have to update it. You can do this with pip command, but remember than Spyder is not compatible with some version. Here is the pip command:
Pip install PyQt5==X.Y.Z
Where X and Y are the same version use to compile your Qt project. The last digit version seems to not be important.

Embedding Python in a Qt Creator project

I'm working on a project that requires C++ to call a program written in Python that relies on Python exclusive modules.
The project is handled using Qt Creator, and Python 3.7.5 and its packages are installed via Miniconda. I've gotten a basic embedding working using Pybind11 where basic interfacing works, however, most external modules cannot be imported.
For example, when importing Numpy through Pybind11, the following error is thrown (reduced for brevity):
Importing the numpy c-extensions failed.
Original error was: /home/brentnallt/miniconda3/envs/car_class_nogpu/lib/python3.7/site-packages/numpy/core/_multiarray_umath.cpython-37m-x86_64-linux-gnu.so: undefined symbol: PyMemoryView_FromObject
A similar error occurs when importing tensorflow through Pybind11:
ImportError: /home/brentnallt/miniconda3/envs/car_class_nogpu/lib/python3.7/lib-dynload/_ctypes.cpython-37m-x86_64-linux-gnu.so: undefined symbol: PyUnicode_FromFormat
It appears to be a problem with Python's C API being found when reading C extension shared libraries. However, modules like lxml which use C source files import just fine. Additionally, I can import problem modules in projects separate from the project I'm working on, implying it's a setup problem. Note that this test project setup doesn't actually use any QT functionality, whereas the main one does.
My PYTHONHOME environment variable looks like:
['/home/brentnallt/miniconda3/envs/car_class_nogpu/lib/python3.7', '/home/brentnallt/miniconda3/envs/car_class_nogpu/lib/python3.7/site-packages', '/home/brentnallt/miniconda3/envs/car_class_nogpu/lib/python37.zip', '/home/brentnallt/miniconda3/envs/car_class_nogpu/lib/python3.7/lib-dynload', '.']
Are there any special considerations I have to make when embedding with Qt Creator? Or is this likely a different problem from a setup error?

Maybe you can consider using PythonQt as an alternative module for calling and importing python libraries from Qt application.
I've used it a lot in my projects and it never failed, but never used it with any kinda data scientific modules maybe you could give it a chance
https://mevislab.github.io/pythonqt/

Compiling an IronPython WPF project to exe

What is the best way to pack up an IronPython application for deployment? After scouring the web the best thing I've come up with (and what I'm currently doing) is using clr.CompileModules() to glue together my entire project's .py files into one .dll, and then having a single run.py do this to run the dll:
import clr
clr.AddReference('compiledapp.dll')
import app
This is still suboptimal, though, because it means I have to
distribute 3 files (the .dll, the .xaml, and the run.py launcher)
install IronPython on the host machine
Plus, this feels so... hacky, after the wonderful integration IronPython already has with Visual Studio 2010. I'm completely mystified as to why there is no integrated build system for IPy apps, seeing as it all boils down to IL anyway.
Ideally, I want to be able to have a single .exe with the .xaml merged inside somehow (I read that C# apps compile XAML to BAML and merge them in the executable), and without requiring IronPython to be installed to run. Is this at least halfway possible? (I suppose it's ok if the exe needs some extra .DLLs with it or something. The important part is that it's in .exe form.)
Some edits to clarify: I have tried pyc.py, but it seems to not acknowledge the fact that my project is not just app.py. The size of the exe it produces suggests that it is just 'compiling' app.py without including any of the other files into the exe. So, how do I tell it to compile every file in my project?
To help visualize this, here is a screenshot of my project's solution explorer window.
Edit II: It seems that unfortunately the only way is to use pyc.py and pass every single file to it as a parameter. There are two questions I have for this approach:
How do I possibly process a command line that big? There's a maximum of 256 characters in a command.
How does pyc.py know to preserve the package/folder structure? As shown in my project screenshot above, how will my compiled program know to access modules that are in subfolders, such as accessing DT\Device? Is the hierarchy somehow 'preserved' in the dll?
Edit III: Since passing 70 filenames to pyc.py through the command line will be unwieldy, and in the interest of solving the problem of building IPy projects more elegantly, I've decided to augment pyc.py.
I've added code that reads in a .pyproj file through the /pyproj: parameter, parses the XML, and grabs the list of py files used in the project from there. This has been working pretty well; however, the executable produced seems to be unable to access the python subpackages (subfolders) that are part of my project. My version of pyc.py with my .pyproj reading support patch can be found here: http://pastebin.com/FgXbZY29
When this new pyc.py is run on my project, this is the output:
c:\Projects\GenScheme\GenScheme>"c:\Program Files (x86)\IronPython 2.7\ipy.exe"
pyc.py /pyproj:GenScheme.pyproj /out:App /main:app.py /target:exe
Input Files:
c:\Projects\GenScheme\GenScheme\__init__.py
c:\Projects\GenScheme\GenScheme\Agent.py
c:\Projects\GenScheme\GenScheme\AIDisplay.py
c:\Projects\GenScheme\GenScheme\app.py
c:\Projects\GenScheme\GenScheme\BaseDevice.py
c:\Projects\GenScheme\GenScheme\BaseManager.py
c:\Projects\GenScheme\GenScheme\BaseSubSystem.py
c:\Projects\GenScheme\GenScheme\ControlSchemes.py
c:\Projects\GenScheme\GenScheme\Cu64\__init__.py
c:\Projects\GenScheme\GenScheme\Cu64\agent.py
c:\Projects\GenScheme\GenScheme\Cu64\aidisplays.py
c:\Projects\GenScheme\GenScheme\Cu64\devmapper.py
c:\Projects\GenScheme\GenScheme\Cu64\timedprocess.py
c:\Projects\GenScheme\GenScheme\Cu64\ui.py
c:\Projects\GenScheme\GenScheme\decorators.py
c:\Projects\GenScheme\GenScheme\DeviceMapper.py
c:\Projects\GenScheme\GenScheme\DT\__init__.py
c:\Projects\GenScheme\GenScheme\DT\Device.py
c:\Projects\GenScheme\GenScheme\DT\Manager.py
c:\Projects\GenScheme\GenScheme\DT\SubSystem.py
c:\Projects\GenScheme\GenScheme\excepts.py
c:\Projects\GenScheme\GenScheme\FindName.py
c:\Projects\GenScheme\GenScheme\GenScheme.py
c:\Projects\GenScheme\GenScheme\PMX\__init__.py
c:\Projects\GenScheme\GenScheme\PMX\Device.py
c:\Projects\GenScheme\GenScheme\PMX\Manager.py
c:\Projects\GenScheme\GenScheme\PMX\SubSystem.py
c:\Projects\GenScheme\GenScheme\pyevent.py
c:\Projects\GenScheme\GenScheme\Scheme.py
c:\Projects\GenScheme\GenScheme\Simulated\__init__.py
c:\Projects\GenScheme\GenScheme\Simulated\Device.py
c:\Projects\GenScheme\GenScheme\Simulated\SubSystem.py
c:\Projects\GenScheme\GenScheme\speech.py
c:\Projects\GenScheme\GenScheme\stdoutWriter.py
c:\Projects\GenScheme\GenScheme\Step.py
c:\Projects\GenScheme\GenScheme\TimedProcess.py
c:\Projects\GenScheme\GenScheme\UI.py
c:\Projects\GenScheme\GenScheme\VirtualSubSystem.py
c:\Projects\GenScheme\GenScheme\Waddle.py
Output:
App
Target:
ConsoleApplication
Platform:
ILOnly
Machine:
I386
Compiling...
Saved to App
So it correctly read in the list of files in the .pyproj... Great! But running the exe gives me this:
Unhandled Exception: IronPython.Runtime.Exceptions.ImportException:
No module named Cu64.ui
So even though Cu64\ui.py is obviously included in compilation, the exe, when run, can't find it. This is what I was afraid of in point #2 in the previous edit. How do I preserve the package hierarchy of my project? Perhaps compiling each package seperately may be needed?
I'll extend the bounty for this question. Ultimately my hope is that we can get a working pyc.py that reads in pyproj files and produces working exes in one step. Then maybe it could even be submitted to IronPython's codeplex to be included in the next release... ;]

Use pyc.py to produce app.exe and don't forget to include app.dll and IronPython libraries.
As for XAML - I've created project just for .xaml files that I compile in VS and then use them from IronPython. For example:
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="/CompiledStyle;component/Style.xaml" />
</ResourceDictionary.MergedDictionaries>

It "boils down to IL", but it isn't compatible with the IL that C# code produces, so it can't be directly compiled to a standalone .exe file.
You'll need to use pyc.py to compile your code to a stub EXE with the DLL that CompileModules creates.
Then distribute those files with IronPython.dll, IronPython.Modules.dll, Microsoft.Dynamic.dll, Microsoft.Scripting.Debugging.dll, Microsoft.Scripting.dll, and of course the XAML file.
To compile other files, just add them as arguments:
ipy.exe pyc.py /main:app.py /target:winexe another.py another2.py additional.py

I posted a Python script which can take an IronPython file, figure out its dependencies and compile the lot into a standalone binary at Ironpython 2.6 .py -> .exe. Hope you find it useful. It ought to work for WPF too as it bundles WPF support.

To create a set of assemblies for your IronPython application so that you can distribute it you can either use pyc.py or SharpDevelop.
To compile using pyc.py:
ipy.exe pyc.py /main:Program.py Form.py File1.py File2.py ... /target:winexe
Given the amount of files in your project you could try using SharpDevelop instead of maintaining a long command line for pyc.py. You will need to create a new IronPython project in SharpDevelop and import your files into the project. You will probably need to import the files one at a time since SharpDevelop lacks a way to import multiple files unless they are in a subfolder.
You can then use SharpDevelop to compile your application into an executable and a dll. All the other required files, such as IronPython.dll, Microsoft.Scripting.dll, will be in the bin/debug or bin/release folder. SharpDevelop uses clr.CompileModules and a custom MSBuild task behind the scenes to generate the binaries.
Any IronPython packages defined in your project should be usable from your application after compilation.
Packaging up the XAML can be done by embedding the xaml as a resource. Then using code similar to the following:
import clr
clr.AddReference('PresentationFramework')
clr.AddReference('System')
from System.IO import FileMode, FileStream, Path
from System.Reflection import Assembly
from System.Windows import Application
from System.Windows.Markup import XamlReader
executingAssemblyFileName = Assembly.GetEntryAssembly().Location
directory = Path.GetDirectoryName(executingAssemblyFileName)
xamlFileName = Path.Combine(directory, "Window1.xaml")
stream = FileStream(xamlFileName, FileMode.Open)
window = XamlReader.Load(stream)
app = Application()
app.Run(window)
SharpDevelop 3.2 does not embed resource files correctly so you will need to use SharpDevelop 4.
If you are using IronPython 2.7 you can use the new clr.LoadComponent method that takes an object and either a XAML filename or stream and wires up that object to the XAML.
Whilst the C# compiler can compile your XAML into a BAML resource doing the same with IronPython has a few problems. If you do not link the XAML to a class via the x:Class attribute then it is possible to compile the XAML into a BAML resource and have that embedded into your assembly. However you will not get any autogenerated code so you will need to create that code yourself. Another problem is that this will not work out of the box with SharpDevelop. You will need to edit the SharpDevelop.Build.Python.targets file and change the from Python to C#. Trying to use the x:Class attribute will not work since the BAML reader cannot access any associated IronPython class. This is because the generated IL in the compiled IronPython application is very different to that in a C# or VB.NET assembly.

I installed Visual Studio 2015 with PTVS (ironpython 2.7). I created a very simple WPF project and wasn't able to compile an exe. I always got the exception "ImportError: No module named wpf".
import clr
clr.AddReferenceToFileAndPath("c:\\path\\to\\IronPython.Wpf.dll")
clr.AddReferenceToFileAndPath('c:\\path\\to\\PresentationCore.dll')
clr.AddReferenceToFileAndPath('c:\\path\\to\\PresentationFramework.dll')
clr.AddReferenceToFileAndPath('c:\\path\\to\\WindowsBase.dll')
from System.Windows import Application, Window
import wpf
class MyWindow(Window):
def __init__(self):
wpf.LoadComponent(self, 'RegExTester.xaml')
def OnSearch(self, sender, e):
self.tbOut.Text = "hello world"
if __name__ == '__main__':
Application().Run(MyWindow())
The fault I got was because the clr clause must be before the import wpf. Steps to compile it:
install pip for CPython 2.7 (not ironpython!)
install ipy2asm
python -m pip install ironpycompiler
compile the application like
ipy2asm compile -t winexe -e -s program.py

py2exe fails to generate an executable

I am using python 2.6 on XP. I have just installed py2exe, and I can successfully create a simple hello.exe from a hello.py. However, when I try using py2exe on my real program, py2exe produces a few information messages but fails to generate anything in the dist folder.
My setup.py looks like this:
from distutils.core import setup
import py2exe
setup(console=['ServerManager.py'])
and the py2exe output looks like this:
python setup.py py2exe
running py2exe
creating C:\DevSource\Scripts\ServerManager\build
creating C:\DevSource\Scripts\ServerManager\build\bdist.win32
...
...
creating C:\DevSource\Scripts\ServerManager\dist
*** searching for required modules ***
*** parsing results ***
creating python loader for extension 'wx._misc_' (C:\Python26\lib\site-packages\wx-2.8-msw-unicode\wx\_misc_.pyd -> wx._misc_.pyd)
creating python loader for extension 'lxml.etree' (C:\Python26\lib\site-packages\lxml\etree.pyd -> lxml.etree.pyd)
...
...
creating python loader for extension 'bz2' (C:\Python26\DLLs\bz2.pyd -> bz2.pyd)
*** finding dlls needed ***
py2exe seems to have found all my imports (though I was a bit surprised to see win32 mentioned, as I am not explicitly importing it). Also, my program starts up quite happily with this command:
python ServerManager.py
Clearly I am doing something fundamentally wrong, but in the absence of any error messages from py2exe I have no idea what.

I put this in all my setup.py scripts:
distutils.core.setup(
options = {
"py2exe": {
"dll_excludes": ["MSVCP90.dll"]
}
},
...
)
This keeps py2exe quiet, but you still need to make sure that dll is on the user's machine.

I've discovered that py2exe works just fine if I comment out the part of my program that uses wxPython. Also, when I use py2exe on the 'simple' sample that comes with its download (i.e. in Python26\Lib\site-packages\py2exe\samples\simple), I get this error message:
*** finding dlls needed ***
error: MSVCP90.dll: No such file or directory
So something about wxPython makes py2exe think I need a Visual Studio 2008 DLL. I don't have VS2008, and yet my program works perfectly well as a directory of Python modules. I found a copy of MSVCP90.DLL on the web, installed it in Python26/DLLs, and py2exe now works fine.
I still don't understand where this dependency has come from, since I can run my code perfectly okay without py2exe. It's also annoying that py2exe didn't give me an error message like it did with the test_wx.py sample.
Further update: When I tried to run the output from py2exe on another PC, I discovered that it needed to have MSVCR90.DLL installed; so if your target PC hasn't got Visual C++ 2008 already installed, I recommend you download and install the Microsoft Visual C++ 2008 Redistributable Package.

wxPython has nothing to do with it. Before Python 2.6, Python used Visual Studio 2003 as their Windows compiler. Beginning with 2.6, they switched to Visual Studio 2008, which requires a manifest file in some situations. This has been well documented. See the following links:
http://wiki.wxpython.org/py2exe
http://py2exe.org/index.cgi/Tutorial#Step52
Also, if you're creating a wxPython application with py2exe, then you want to set the windows parameter, NOT the console one. Maybe my tutorial will help you:
http://www.blog.pythonlibrary.org/2010/07/31/a-py2exe-tutorial-build-a-binary-series/

It looks like this is only a dependency for Python 2.6. I wasn't getting this error under 2.5, but after the upgrade I am.
This email thread has some background for why the problem exists and how to fix it:
http://www.nabble.com/py2exe,-Py26,-wxPython-and-dll-td20556399.html
I didn't want to have to install the vcredist. My application currently requires no installation and can be run by non-administrators, which is behavior I don't want to lose. So I followed the suggestions in the links and got the necessary Microsoft.VC90.CRT.manifest and msvcr90.dll by installing Python "for this user only". I also needed msvcp90.dll that I found in the WinSxS folder of an "all users" Python 2.6 install. Since I already had two of the three, I included msvcm90.dll to prevent future errors though I didn't get any immediate errors when I left it out. I put the manifest and the three DLLs in the libs folder used by my frozen application.
The trick I had to perform was including an additional copy of the manifest and msvcr90.dll in the root of my application folder next to by py2exe generated executable. This copy of the DLL is used to bootstrap the application, but then it appears to only look in the libs folder.
Hopefully that discovery helps someone else out.
Also, I had the same problem with having py2exe log a real error message. Then I realized that stderr wasn't getting redirected into my log file. Add "> build.log 2>&1" on the command line where you invoke py2exe.

import sys
sys.path.append('C:\\WINDOWS\\WinSxS\\x86_microsoft.vc90.crt_1fc8b3b9a1e18e3b_9.0.30729.4148_none_5090ab56bcba71c2')
On each Windows, you can find the file MSVCP90.dll in some subdirectory in C:\\WINDOWS\\WinSxS\\
In my case, the directory was: x86_microsoft.vc90.crt_1fc8b3b9a1e18e3b_9.0.30729.4148_none_5090ab56bcba71c2.
Go to C:\\WINDOWS\\WinSxS\\ and use windows file search to find MSVCP90.dll.

Just for your info, for me it worked to copy the files
Microsoft.VC90.CRT.manifest
msvcr90.dll
into the directory with the .exe on the user's machine (who has no python or VC redistributable installed).
Thanks for all the hints here!

The output says you're using WX. Try running py2exe with your script specified as a GUI app instead of console. If I'm not mistaken, that tends to cause problems with py2exe.

Try this: http://www.py2exe.org/index.cgi/Tutorial#Step52
It worked for me

There is some info on the wxPython wiki.
Deploy a Python app
py2exe with wxPython and Python 2.6

On my win8.1, I do not find the path
c:/Program Files/Microsoft Visual Studio 9.0/VC/redist/x86/Microsoft.VC90.CRT
On the contrary , the dll is found in
C:/WINDOWS/WinSxS/x86_Microsoft.VC90.CRT_XXXXXXX
The XXX may vary according to your PC
You may search in the path , then add the path in you setup.py
import sys
sys.path.append('C:/WINDOWS/WinSxS/x86_Microsoft.VC90.CRT_XXXXXXX')

import sys
sys.path.append('c:/Program Files/Microsoft Visual Studio 9.0/VC/redist/x86/Microsoft.VC90.CRT')