I'm using a Cygwin64 terminal and trying to reference a function from a simple .dll written in C through a wrapper in Python. The goal is to have 'Hello World!' print out on the terminal once I run the python script.
The C file:
// function.c
#include <stdio.h>
int hello()
{
printf("Hello World!\n");
}
I'm compiling the function into a .dll using gcc:
gcc -c function.c
gcc -shared -o function.dll function.o
Finally, I'm using the ctypes library in python to call the 'hello' function from the compiled .dll file:
# wrapper.py
from ctypes import *
import os
if __name__ == '__main__':
c_lib = cdll.LoadLibrary(os.path.abspath('function.dll'))
c_lib.hello()
I'm a novice when it comes to using ctypes, but I've tried several different configuration of the above file, using WinDLL and CDLL; all methods I've tried are resulting in the same output when I run the python script in Cygwin:
$ python wrapper.py
Traceback (most recent call last):
File "C:\cygwin64\home\Alex\test\marshalling_c_files\wrapper.py", line 6, in <module>
c_lib = cdll.LoadLibrary(os.path.abspath('function.dll'))
File "C:\Users\Alex\AppData\Local\Programs\Python\Python39\lib\ctypes\__init__.py", line 452, in LoadLibr
ary
return self._dlltype(name)
File "C:\Users\Alex\AppData\Local\Programs\Python\Python39\lib\ctypes\__init__.py", line 374, in __init__
self._handle = _dlopen(self._name, mode)
OSError: [WinError 193] %1 is not a valid Win32 application
My understanding from looking into this error a little had me thinking that somehow the .dll file I had compiled was not compatible with the version of Cygwin I was running or Windows 10, but I was able to call the 'hello' function from the compiled .dll in another C program.
I've been trying to make this as simple as possible to figure out what's going wrong, but I've stopped making progress on my own. Right now I'm trying to figure out if my .dll is being compiled as 32-bit instead of 64-bit. When I use the -m64 tag for GCC, I'm getting an error saying that the feature is not implemented in GCC for Cygwin.
