Description

v-volatus

opened on May 30, 2022

Issue body actions

Documentation

URL: https://docs.python.org/3/extending/embedding.html
System: Ubuntu 22.04 using Python 3.10

Problem:

Using the recommended linking option /opt/bin/python3.10-config --ldflags leads to undefined references when compiling.

command used in terminal:

g++ $(python3.10-config --cflags ) -o 'test.o' 'test.cpp' $(python3.10-config --ldflags)


Output of python3.10-config --ldflags:

-L/usr/lib/python3.10/config-3.10-x86_64-linux-gnu -L/usr/lib/x86_64-linux-gnu -lcrypt -ldl -lm -lm


Solution:

Adding the option --embed solves the issue. By this, -lpython3.10 is also given to the compiler.

command used in terminal:

g++ $(python3.10-config --cflags ) -o 'test.o' 'test.cpp' $(python3.10-config --embed --ldflags)


output of python3.10-config --embed --ldflags:

-L/usr/lib/python3.10/config-3.10-x86_64-linux-gnu -L/usr/lib/x86_64-linux-gnu -lpython3.10 -lcrypt -ldl -lm -lm


test.cpp:

#include < Python.h >

int main()
{
	Py_Initialize();
	PyRun_SimpleString("print('Hello World from Embedded Python!!!')");
	Py_Finalize();
	
	return 0;
}

Activity

1. v-volatus

   added

   docsDocumentation in the Doc dirDocumentation in the Doc dir

   on May 30, 2022
2. v-volatus

   changed the title [-]Embedding Python in C++: Compiling and Linking under Ubuntu 22.04[/-] [+]Undefined References when using recommended linking option: Embedding Python in C++ (Ubuntu 22.04)[/+] on May 30, 2022
3. v-volatus

   changed the title [-]Undefined References when using recommended linking option: Embedding Python in C++ (Ubuntu 22.04)[/-] [+]Undefined References when using recommended linking option: Embedding Python in C++ [/+] on May 30, 2022
4. AA-Turner

   added

   3.10 (EOL)end of lifeend of life

   topic-C-API

   on May 30, 2022
5. TianmingQu commented on Oct 24, 2022

   

   TianmingQu

   on Oct 24, 2022 · Hidden as off-topic

   show commentMore actions
6. erlend-aasland commented on Oct 25, 2022

   

   erlend-aasland

   on Oct 25, 2022

   Contributor

   More actions

   Adding the option --embed solves the issue. By this, -lpython3.10 is also given to the compiler.

   Yes, the docs are out of date. This was changed in Python 3.8 -- see the 3.8 What's New:

   https://docs.python.org/3/whatsnew/3.8.html#debug-build-uses-the-same-abi-as-release-build

   Adding --embed when producing the linker flags should help. I'll create a PR for updating the docs.
7. erlend-aasland commented on Oct 25, 2022

   

   erlend-aasland

   on Oct 25, 2022 · Hidden as off-topic

   show commentMore actions
8. erlend-aasland

   added 2 commits that reference this issue on Oct 25, 2022

   pythongh-93358: Fix python-config docs for how to embed Python

   6550e3b

   gh-93358: Fix python-config docs for how to embed Python (#98649)

   e063c23
9. miss-islington

   added 2 commits that reference this issue on Oct 29, 2022

   pythongh-93358: Fix python-config docs for how to embed Python (pytho…

   53ba27c

   pythongh-93358: Fix python-config docs for how to embed Python (pytho…

   2139640
10. erlend-aasland commented on Oct 29, 2022

    

    erlend-aasland

    on Oct 29, 2022

    Contributor

    More actions

    The docs were updated by the following PRs:

    • gh-93358: Fix python-config docs for how to embed Python #98649
    • [3.11] gh-93358: Fix python-config docs for how to embed Python (GH-98649) #98857
    • [3.10] gh-93358: Fix python-config docs for how to embed Python (GH-98649) #98858
11. miss-islington

    added 2 commits that reference this issue on Oct 29, 2022

    gh-93358: Fix python-config docs for how to embed Python (GH-98649)

    c76e70a

    gh-93358: Fix python-config docs for how to embed Python (GH-98649)

    f8fb0d8
12. erlend-aasland

    closed this as completedon Oct 30, 2022

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