Why 'Segmentation fault' occurs in my cpython module code? (PyObject_Print)

Question

I am trying to print PyObject and 'Segmentation fault' occured. I want to use PyObject_Print. How can I solve the problem?

int main(){
    Py_Initialize();
    ///////////////////////////////////////////
    PyObject *tmp1 = PyLong_FromLong((1<<29)*3);
    PyObject *tmp2 = PyLong_FromLong((1<<20)*41+1264);
    PyObject *u;
    u = PyNumber_Multiply(tmp1,tmp2);
    PyObject_Print(u,stdout,Py_PRINT_RAW); // Segmentation fault here

    const char* uu = PyUnicode_AsUTF8(PyObject_Repr(u));
    printf("%s\n", uu); // it works
    Py_Finalize();
    return 0;
}

I am debugging with vscode.

My tasks.json is

       {
            "type": "cppbuild",
            "label": "C/C++: gcc.exe build active file",
            "command": "C:\\msys64\\mingw64\\bin\\gcc.exe",
            "args": [
                "-fdiagnostics-color=always",
                "-g",
                "${file}",
                "-o",
                "${fileDirname}\\${fileBasenameNoExtension}.exe",
                "-I",
                "C:/Users/.../AppData/Local/Programs/Python/Python37/include",
                "-L",
                "C:/Users/.../AppData/Local/Programs/Python/Python37/libs",
                "-lpython37",
            ],
            "options": {
                "cwd": "${fileDirname}"
            },
            "problemMatcher": [
                "$gcc"
            ],
            "group": {
                "kind": "build",
                "isDefault": true
            },
            "detail": "Task generated by Debugger."
        }

I redownloaded whole python3.7 and it did not help I tried python3.11 cpython in anaconda, and it still 'Segmentation fault' occured.

Edit

I found python3.10.10 in mingw64. I changed my local python version to 3.10.10. However, still I have an error.

message: Thread 1 received signal SIGSEGV, Segmentation fault. ntdll!TpWorkOnBehalfClearTicket () from C:\WINDOWS\SYSTEM32\ntdll.dll

I guess the detail error was different from python3.7

Answer 1

Python is built on Win using (native) VStudio, so this configuration (MinGW) is unsupported. Some references:

• [Python.Wiki]: WindowsCompilers

• [ReadTheDocs.PythonDev]: Compile CPython on Windows

• [SO]: setup python 3 in mingw

• [SO]: Why qt project can throw errors like undefined reference to `__imp_ Py_Initialize' and so on? (@CristiFati's answer)

I tried reproducing the behavior in several environments.

main00.c:

#include <stdio.h>
#include <Python.h>


int main()
{
    Py_Initialize();

    PyObject *tmp1 = PyLong_FromLong((1 << 29) * 3);
    PyObject *tmp2 = PyLong_FromLong((1 << 20) * 41 + 1264);
    PyObject *prod = PyNumber_Multiply(tmp1, tmp2);
    const char *prods = PyUnicode_AsUTF8(PyObject_Repr(prod));

    printf("printf: %s\n", prods);
    printf("Before PyObject_Print\n");
#if defined FILE_NAME
    FILE *fo = fopen(FILE_NAME, "w");
#else
    FILE *fo = stdout;
#endif
    PyObject_Print(prod, fo, Py_PRINT_RAW);
#if defined FILE_NAME
    fclose(fo);
#endif
    printf("\nAfter PyObject_Print\n");

    Py_Finalize();
    printf("\nDone.\n\n");
    return 0;
}

I used Python 3.10 (where possible).

Outputs:

1. MinGW:

   [cfati@CFATI-5510-0:e:\Work\Dev\StackExchange\StackOverflow\q076148413]> sopr.bat
   ### Set shorter prompt to better fit when pasted in StackOverflow (or other) pages ###
   
   [prompt]> "f:\Install\pc064\MinGW\MinGW-W64\x86_64-8.1.0-posix-seh-rt_v6-rev0\mingw-w64.bat"
   
   [prompt]> echo off
   Microsoft Windows [Version 10.0.19045.2913]
   (c) Microsoft Corporation. All rights reserved.
   
   [prompt]> md mgwgcc
   
   [prompt]> cd mgwgcc
   
   [prompt]>
   [prompt]> gcc -g ..\main00.c -Ic:\Install\pc064\Python\Python\03.10\include -Lc:\Install\pc064\Python\Python\03.10\libs -lpython310 -o pc064_py0310.exe
   
   [prompt]>
   [prompt]> pc064_py0310.exe
   
   [prompt]>
   [prompt]> set PATH=%PATH%;c:\Install\pc064\Python\Python\03.10
   
   [prompt]> pc064_py0310.exe
   printf: 69244880085319680
   Before PyObject_Print
   :: ------- @TODO - cfati: Crashed here -------
   

2. VStudio:

   [cfati@CFATI-5510-0:e:\Work\Dev\StackExchange\StackOverflow\q076148413]> sopr.bat
   ### Set shorter prompt to better fit when pasted in StackOverflow (or other) pages ###
   
   [prompt]> "c:\Install\pc032\Microsoft\VisualStudioCommunity\2019\VC\Auxiliary\Build\vcvarsall.bat" x64 > nul
   
   [prompt]> md vs
   
   [prompt]> cd vs
   
   [prompt]> cl -nologo ..\main00.c -Ic:\Install\pc064\Python\Python\03.10\include  -link -NOLOGO -LIBPATH:c:\Install\pc064\Python\Python\03.10\libs python310.lib -OUT:pc064_py0310.exe
   main00.c
   
   [prompt]>
   [prompt]> set PATH=%PATH%;c:\Install\pc064\Python\Python\03.10
   
   [prompt]> pc064_py0310.exe
   printf: 69244880085319680
   Before PyObject_Print
   69244880085319680
   After PyObject_Print
   
   Done.
   

3. WSL:

   (py_pc064_03.10_test0) [cfati@cfati-5510-0:/mnt/e/Work/Dev/StackExchange/StackOverflow/q076148413]> ~/sopr.sh
   ### Set shorter prompt to better fit when pasted in StackOverflow (or other) pages ###
   
   [064bit prompt]> uname -a
   Linux cfati-5510-0 5.15.90.1-microsoft-standard-WSL2 #1 SMP Fri Jan 27 02:56:13 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux
   [064bit prompt]> md wslgcc
   [064bit prompt]> cd wslgcc
   [064bit prompt]>
   [064bit prompt]> gcc -g ../main00.c -I/usr/include/python3.10 -L/usr/lib/python3.10 -lpython3.10 -o pc064_py0310
   [064bit prompt]>
   [064bit prompt]> ./pc064_py0310
   printf: 69244880085319680
   Before PyObject_Print
   69244880085319680
   After PyObject_Print
   
   Done.
   

4. MSYS2:

   [cfati@cfati-5510-0:/e/Work/Dev/StackExchange/StackOverflow/q076148413]> ~/sopr.sh
   ### Set shorter prompt to better fit when pasted in StackOverflow (or other) pages ###
   
   [064bit prompt]> uname -a
   MSYS_NT-10.0-19045 cfati-5510-0 3.4.6.x86_64 2023-04-01 11:43 UTC x86_64 Msys
   [064bit prompt]> md msysgcc
   [064bit prompt]> cd msysgcc
   [064bit prompt]>
   [064bit prompt]> gcc -g ../main00.c -I/usr/include/python3.11 -L/usr/lib/python3.11 -lpython3.11 -o pc064_py0311
   [064bit prompt]>
   [064bit prompt]> ./pc064_py0311.exe
   printf: 69244880085319680
   Before PyObject_Print
   69244880085319680
   After PyObject_Print
   
   Done.
   
   [064bit prompt]>
   [064bit prompt]> gcc -g ../main00.c -I/c/Install/pc064/Python/Python/03.11/include -L/c/Install/pc064/Python/Python/03.11/libs -lpython3.11 -o pc064_py0311win  In file included from /c/Install/pc064/Python/Python/03.11/include/Python.h:38,
                    from ../main00.c:2:
   /c/Install/pc064/Python/Python/03.11/include/pyport.h:601:2: error: #error "LONG_BIT definition appears wrong for platform (bad gcc/glibc config?)."
     601 | #error "LONG_BIT definition appears wrong for platform (bad gcc/glibc config?)."
   

5. Cygwin:

   [cfati@cfati-5510-0:/cygdrive/e/Work/Dev/StackExchange/StackOverflow/q076148413]> ~/sopr.sh
   ### Set shorter prompt to better fit when pasted in StackOverflow (or other) pages ###
   
   [064bit prompt]> uname -a
   CYGWIN_NT-10.0-19045 cfati-5510-0 3.4.6-1.x86_64 2023-02-14 13:23 UTC x86_64 Cygwin
   [064bit prompt]> md cyggcc
   [064bit prompt]> cd cyggcc
   [064bit prompt]>
   [064bit prompt]> gcc -g ../main00.c -I/usr/include/python3.9 -L/usr/lib/python3.9 -lpython3.9 -o pc064_py0309
   [064bit prompt]>
   [064bit prompt]> ./pc064_py0309
   printf: 69244880085319680
   Before PyObject_Print
   69244880085319680
   After PyObject_Print
   
   Done.
   
   [064bit prompt]>
   [064bit prompt]> gcc -g ../main00.c -I/cygdrive/c/Install/pc064/Python/Python/03.09/include -L/cygdrive/c/Install/pc064/Python/Python/03.09/libs -lpython3.9 -o pc064_py0309win
   In file included from /cygdrive/c/Install/pc064/Python/Python/03.09/include/Python.h:50,
                    from ../main00.c:2:
   /cygdrive/c/Install/pc064/Python/Python/03.09/include/pyport.h:741:2: error: #error "LONG_BIT definition appears wrong for platform (bad gcc/glibc config?)."
     741 | #error "LONG_BIT definition appears wrong for platform (bad gcc/glibc config?)."
         |  ^~~~~
   # ----- @TODO - cfati: Truncated some lines ----
   

As seen, "regular" configurations work. In the last 2 examples, trying to use the native Python doesn't even compile.
I didn't attempt any debugging, and I'm not going to. You should stick with officially supported configurations, pick whichever suits you best. I'd go with the official one (VStudio), here are some examples:

• [SO]: Calling Python function with parametrs from C++ project (Visual Studio) (@CristiFati's answer)

• [SO]: I then use python to generate dll, c for debugging , after I generate the dll from VS, I am using LoadLibraryA will report error code 1411 (@CristiFati's answer)