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devel / comp.lang.python / Re: [Help Request] Embedding Python in a CPP Application Responsibly & Functionally

Re: [Help Request] Embedding Python in a CPP Application Responsibly & Functionally

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From: dieter@handshake.de (Dieter Maurer)
Newsgroups: comp.lang.python
Subject: Re: [Help Request] Embedding Python in a CPP Application Responsibly &
Functionally
Date: Thu, 26 Jan 2023 08:50:51 +0100
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by: Dieter Maurer - Thu, 26 Jan 2023 07:50 UTC

John McCardle wrote at 2023-1-25 22:31 -0500:
> ...
>1) To get the compiled Python to run independently, I have to hack
>LD_LIBRARY_PATH to get it to execute. `LD_LIBRARY_PATH=./Python-3.11.1
>./Python-3.11.1/python` .

The need to set `LD_LIBRARY_PATH` usually can be avoided via
a link time option: it tells the linker to add library path
information into the created shared object.

Read the docs to find out which option this is (I think it
was `-r` but I am not sure).

>Even when trying to execute from the same
>directory as the binary & executable, I get an error, `/python: error
>while loading shared libraries: libpython3.11.so.1.0: cannot open shared
>object file: No such file or directory`.

It might be necessary, to provide the option mentioned above
for all shared libraries involved in your final application.

Alternatively, you could try to put the shared objects
into a stadard place (searched by default).

>2) When running the C++ program that embeds Python, I see these messages
>after initializing:
>`Could not find platform independent libraries <prefix>
>Could not find platform dependent libraries <exec_prefix>`

Again: either put your installation in a standard place
or tell the Python generation process about your non-standard place.

>This is seemingly connected to some issues regarding libraries: When I
>run the Python interpreter directly, I can get some of the way through
>the process of creating a virtual environment, but it doesn't seem to
>leave me with a working pip:
>
>`$ LD_LIBRARY_PATH=./Python-3.11.1 ./Python-3.11.1/python
> >>> import venv
> >>> venv.create("./venv", with_pip=True)
>subprocess.CalledProcessError: Command
>'['/home/john/Development/7DRL/cpp_embedded_python/venv/bin/python',
>'-m', 'ensurepip', '--upgrade', '--default-pip']' returned non-zero exit
>status 127.`

Run the command manually and see what errors this gives.

> ...

>3) I'm not sure I even need to be statically linking the interpreter.

There should be no need (if all you want in the embedding).

Subject	Author
Re: [Help Request] Embedding Python in a CPP Application Responsibly &	Dieter Maurer