Re: Can't open compiled [pyo~] object

Thanks for all the info and help! It now works, but I'm replying below 
some of your answers.

On 7/2/25 13:17, IOhannes m zmoelnig via Pd-list wrote:
> On 5/31/25 11:07, Alexandros Drymonitis wrote:
>>
>> I've changed the Makefile to the following (maybe there are mistakes, 
>> like where the -rdynamic should go or others):
>
> why is it there in the first place?
I have no idea how all this works, so I've been trying things out based 
on information I got from searching the web.
>
>>
>> ```
>> # Makefile for pyo~
>>
>> lib.name = pyo~
>>
>> class.sources = pyo~.c
>>
>> cflags =  -rdynamic -I"$(PD_INCLUDE)" -I.. -Wno-cast-function-type 
>> -Wno- unused-parameter -I/usr/include/python3.11 $(shell pkg-config 
>> --cflags --embed python3.11)
>> ldflags = -lpython3.11 $(shell pkg-config --ldflags --embed python3.11)
>> libs = -L/usr/lib/ $(shell pkg-config --libs --embed python3.11)
>
>
> that appears to do an awful lot of unneeded ('-I"$(PD_INCLUDE")' is 
> already handled by pd-lib-builder), redundant (e.g. why is 
> "-L/usr/lib/" there in the first place? if it is not searched for by 
> default, then there's probably a good reason; why do you have *both* 
> the hardcoded "/usr/include/python3.11" and a call to pkg-config?) and 
> broken (I don't know of any pkg-config that accepts the "--embed" 
> flag) stuff.
>
> anyhow, i've cleaned up the Makefile, like so:
>
>
> ```
> # Makefile for pyo~
>
> lib.name = pyo~
>
> class.sources = pyo~.c
>
> PKG_CONFIG := pkg-config
> PYTHON=python3
>
> PY_CFLAGS := $(shell $(PKG_CONFIG) --cflags $(PYTHON))
> PY_LIBS   := $(shell $(PKG_CONFIG) --libs $(PYTHON))
>
> cflags += $(PY_CFLAGS) -I../
> ldlibs += $(PY_LIBS)
>
> datafiles = pyo-help.pd README.md
>
> PDLIBBUILDER_DIR=../pd-lib-builder/
> include $(PDLIBBUILDER_DIR)/Makefile.pdlibbuilder
> ```
Your Makefile works (I guess you're not surprised :).
>
> if your python installation does not provide pkgconf scripts for 
> "python3", you can pass it on the cmdline like so:
> ```
> make PYTHON=python3.11
> ```
>
> if you are still not happy with the flags provided by pkgconf, you can 
> pass them manually, like so:
> ```
> make PY_CFLAGS="$(python3.11-config --embed --cflags)" 
> PY_LIBS="$(python3.11-config --embed --libs)"
> ```
>
>
> having said that, I've compiled the external with python3.13 
> (Debian/trixie/sid), but...
I wanted to build it for Python3.13 too, but I couldn't find the 
libpython3.13.so file on my system. I'm on Debian 12 and compiled 
Python3.13 myself. Any idea where this is?
>
>>
>> The object builds, but I'm still getting the `undefined symbol: 
>> _Py_NoneStruct` error 
>
>
> and I get the same error as well.
>
>
> as said previously, "I'm not up-to-date when it comes to python 
> C-development".
> however, force-loading the python-library apparently fixes the problem 
> for me:
>
> ```
> LD_PRELOAD=/usr/lib/x86_64-linux-gnu/libpython3.13.so pd pyo~-help.pd
> ```
I needed to do that as well.
>
> (the help-patch depends on cyclone, but anyhow).
>
> apparently, you should adjust the path to the libpython.so on your 
> system.
>
> also note, that LD_PRELOAD is general not a good idea
> (and you should *definitely not* set the environment variable globally,
> unless you are really into kneecapping and the like)
How can one avoid this then?
>
>>
>> In a filed used to create the object, called m_pyo.h, line 71 reads:
>>
>> ```
>> #ifdef __linux__
>>          libpython_handle = dlopen("libpython3.11.so", RTLD_LAZY | 
>> RTLD_GLOBAL);
>>
>> ```
>
> no idea where you got the sources from, but afaict current [master] 
> says "libpython3.9.so".
I changed it myself, so that it points to Python3.11, not 3.9.
>
> in any case, the idea of the code is that it will dynamically load the 
> python runtime library to resolve all the symbols.
> but this is broken.
> afaict, that's because the binaries *really* use the "_Py_NoneStruct" 
> symbol directly, rather than deferring the symbol resolution till the 
> dlopen() succeeded.
> (the consequence is, that fixing the numbers in the dlopen() call, 
> won't help).
>
>
> this wouldn't be a problem is the myo~.pd_linux was linked directly 
> against the libpython.
> however, `pkg-config --libs python3` does not tell the linker to do 
> so, for whatever reasons (afaict, the idea is really to use dlopen() 
> to open the library at runtime, rather than adding a hard dependency 
> on the lib).
>
> so my take is, that there is simply some bug on pyo (and probably it 
> doesn't show on macOS, because they allow weak-linkage)
>
>
> in any case, overriding the linker flags fixes this easily:
> ```
> make PY_LIBS="-lpython3.13"
> ```
That's true (I guess you're not surprised again!). I changed that to 
3.11 though.
>
> alternatively, using "python3.13-config --embed"  should also give you 
> the correct flags:
>
> ```
> make PDLIBBUILDER_DIR=/usr/share/pd-lib-builder/ 
> PY_CFLAGS="$(python3.13-config --embed --cflags)" 
> PY_LIBS="$(python3.13-config --embed --libs)"
> ```
>
> (this line is basically just repeating what i already wrote above)
>
>
> gmasdr
> IOhannes
>
>
>
> [master] 
> <https://github.com/belangeo/pyo/blob/a7cbe87a52330defdede1f31d29ed719712a08a8/embedded/m_pyo.h#L71>
>
>
>
>
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