#helping with debuging python module

79 messages · Page 1 of 1 (latest)

sudden isle
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im trying to make a python module with cpp and pybind11, how should i debug my module when i execute the python file

light kilnBOT
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rigid rune
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I didn't have to do anything special, just run the whole python process in your debugger

sudden isle
rigid rune
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Which one do you normally use?

sudden isle
rigid rune
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C++ one

sudden isle
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the python source code is the executable

rigid rune
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How do you use it normally?

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In some kind of IDE?

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Or in the terminal?

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And which C++ debugger is it?

sudden isle
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in vsc

rigid rune
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So just set python as the executable in launch.json

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And you can give it command line arguments to run your script/whatever

sudden isle
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in the python file

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and even in the cpp

rigid rune
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I expect it to only work in .cpp files

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Did you compile your python module with -g?

sudden isle
rigid rune
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If it doesn't work, then probably not

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Can you recompile it and try again? If this doesn't work, show the exact compilation command you used

sudden isle
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i did recompile it and try again 6 or 7 time

rigid rune
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What CMAKE_BUILD_TYPE do you use? Debug?

sudden isle
rigid rune
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Ok. Delete the build directory and rebuild in verbose mode. Show the compilation commands

sudden isle
rigid rune
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Do you know how to use cmake from the terminal?

sudden isle
rigid rune
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Then instead of cmake --build ... do cmake --build ... --verbose

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It should show the compilation commands

sudden isle
rigid rune
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What python are you testing the module with?

sudden isle
rigid rune
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I mean msys2 python or not?

sudden isle
rigid rune
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Okay, that's good

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Where do you place your breakpoint? Are you sure this function is getting called?

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Try printing something from your module

sudden isle
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i put a breakpoint in the constructure of a class in the python file

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then put another breakpoint in somewhere in the constructure function

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idk if i spelled constructure correct

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btw what did you tell me to debug python with gdb

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gdb python src.py?

rigid rune
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Yeah, that should work

sudden isle
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however, it dont work

rigid rune
sudden isle
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i work

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but i dont debug

rigid rune
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Does it not work if you place breakpoint on the line that prints stuff?

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To be clear, when you run it in a debugger, you see the text being printed, but the breakpoint on the exact same C++ line doesn't get triggered?

sudden isle
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i dont stop on breakpoint

rigid rune
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Alright

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I've created this file, called 1.cpp:

#include <iostream>
#include <pybind11/pybind11.h>

PYBIND11_MODULE(example, m)
{
    m.def("foo", []
    {
        std::cout << "Hello!\n";
    });
}
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Compiled with g++ 1.cpp `pkg-config --libs --cflags python3-embed` -Ipybind11/include -shared -o example.pyd -g in MSYS2 UCRT64

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Then did gdb --args python3 -c 'import example; example.foo()'

b 1.cpp:8
y
r
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And the breakpoint is being hit

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Test the exact same thing, see if it's being hit for you or not

sudden isle
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whatsgoingon

rigid rune
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❓

sudden isle
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i have no idea what you say

rigid rune
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I've tried debugging a simple module and it works for me

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I've given you the exact steps on how to do that

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Test if this process works for you or not

sudden isle
rigid rune
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That shouldn't matter, continue with the steps and see if it works

sudden isle
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i tried compile but it doesnt work

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can i use cmake

rigid rune
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Let's avoid cmake for now

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Wdym by "doesn't work"? Show errors

sudden isle
rigid rune
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Please read my last comment again