[PD] Can't open compiled [pyo~] object

[IOhannes m zmölnig]

On 2/21/23 20:21, Alexandros wrote:
> 
> On 21/2/23 20:41, IOhannes m zmölnig wrote:
>> Am 21. Februar 2023 08:41:48 MEZ schrieb Alexandros <adrcki at gmail.com>:
>>> ldflags= $(shell python-config --ldflags)
>>> libs= $(shell python-config --libs)
>>>
>> [...]
>>> In the pyo~.c file there's a `#include "Python.h"`. Does this mean 
>>> that I should direct the Makefile to find this file? Because no 
>>> Python.h file comes with the source code.
>>
>> Hopefully so.
>> python.h is a file provided by python, and it is paramount that you 
>> build against the header file that matches your python installation.
>> So you must install the python development files (python3-dev, or 
>> somesuch).
>>
>> I'm not up-to-date when it comes to python C-development, but I  
>> 'python-config' smells like a deprecated tool.
> Initially that was python3-config, but in my system, `python` is 
> Python3, so I thought I change it to `python-config`. Is this still a 
> deprecated tool?

1. i was referring to "<foo>-config" being frowned upon in general, as 
it creates ad-hoc tools with non-normalized interfaces. typically, a 
preferred way is to use pkg-config or similar tools (that provide a 
standard way to query compiler/linker flags to build things).
this is a general observation, but of course the Python folks can still 
ship (and prefer) their own tool (hence my "I'm not up-to-date when it 
comes to python C-development")

2. i *think* the canonical name for the tool is 'python3-config', and 
you should not arbitrarily change that just becaues you happen to have a 
'python-config' script lying somewhere on your disk.
(afaict, this script can be installed on Debian via the 
'python-dev-is-python3' convenience package. i would *not* recommend 
relying on this, and use canonical names instead (but again, "I'm not 
up-to-date when it comes to python C-development" so i might be wrong 
about what the canonical name is).


it turns out that 'pkg-config --cflags python3' resp 'pkg-config --libs 
python3' should do the trick as well.


in any case, your real problem is, that your library does not link 
against the python dynamic library (e.g. libpython3.11).
i don't know why "python3-config --libs" does not report the apropriate 
linker flags ("I'm not up-to-date when it comes to python 
C-development"), but "python3-config --embed --libs" (and you probably 
should add the '--embed' flag to all invocations of python3-config), as 
well as "pkg-config --libs python3-embed".



finally: there's an issuetracker for pyo on 
<https://github.com/belangeo/pyo/issues> which might be a better place 
to ask such specific questions.


mfg
IOhannes
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