strongly-typed
commented
2 years ago The "simpel_example" from the project already give different results when using msvcrt.dll. So it is not a problem of my DLL.
The code uses pointers and memset
# Add 4 'O' to the string starting from position 6
p = ctypes.cast(ctypes.addressof(mut_str) + 5, ctypes.POINTER(ctypes.c_char))
libc.memset(p, ctypes.c_char(b"O"), 4)
# Print the modified string
libc.puts(mut_str)The expected result (which is produced by CPython) is XXXXXOOOO. IronPython does not write to the correct memory.
PS C:\Users\Sascha\Desktop\working_directory\Python-using-C-CPP-libraries-with-ctypes\simple_example> $Env:IRONPYTHONPATH="C:\Users\Sascha\Desktop\working_directory\ironpython3\Src\StdLib\Lib"
PS C:\Users\Sascha\Desktop\working_directory\Python-using-C-CPP-libraries-with-ctypes\simple_example> ..\..\ironpython3\bin\Release\net6.0\ipy.exe .\t0.py
Succesfully loaded the system C library from "C:\Windows\system32\msvcrt.dll"
Hello from Python to C
Using the C printf function from Python ...
XXXXX
XXXXX
PS C:\Users\Sascha\Desktop\working_directory\Python-using-C-CPP-libraries-with-ctypes\simple_example> python .\t0.py
Succesfully loaded the system C library from "C:\Windows\system32\msvcrt.dll"
Hello from Python to C
Using the C printf function from Python ...
XXXXX
XXXXXOOOO
slozier
I tried to use
ctypesto interface to some C/C++ code as DLL with IronPython on Windows. I got random segfaults and errors in malloc. I am trying to boil it down and moved to a simple project that works with CPython but fails with IronPython2.7 and IronPython3.4-beta.The project to test with is Python-using-C-CPP-libraries-with-ctypes. Great shout-out to @sol-prog
I am using Windows 10 21H1 OS build 19044.1865 and Visual Studio Community 2022. Detailed environment information at the bottom.
I used the released IronPython versions and also built IronPython3.4 from source (so trying that the same compiler is used for the DLL and IronPython binaries).
When I compile the DLL using MSVC (cbmp.dll) and run it with IronPython3.4 the code does not run due to some internal memory corruption.
When running with Python3 the code works just fine and produces valid output.
In
cbmp.pyI had to modify the loading of the library to:I compiled the DLL in the following way (from the "x64 Native Tools Command Prompt for VS 2022")
x86 (32-bit) Test
I also build IronPython x86 and the DLL with x86 to test:
From "x86 Native Tools Command Prompt for VS 2022":
Build Python for x86. Only the net46 version seemed to be build:
This gives some access violation. The code works with CPython and the DLL seems to be fine. I guess something in
ctypesis broken in IronPython?!Or what are the best/correct compiler parameters I should use to compile the DLL with? To match calling conventions, pointer sizes, et cetera?
Environment
"x64 Native Tools Command Prompt for VS 2022"