Need help using swig

emanuel · March 22, 2025, 11:46am

Hello, I’m brand new to CMake.
I’ve been building interpreters into LibreCAD for a while now.
It works well with QtCreator.
LibreCAD also has a Pixi build with CMake.

github.com/emanuel4you/LibreCAD

CMakeLists.txt

developer


      
          qt_standard_project_setup(I18N_TRANSLATED_LANGUAGES ar ca cs da de el en_au en es_ar es_bo es_cl es_co es_cr es_do es_ec es_gt es_hn es_mx es_ni es_pa es_pe es_pr es_py es_sv es es_us es_uy es_ve et eu fi fr gl he hi hu id_ID it ja ka ko lv mk nl no pa pl pt_br pt_pt ro_ro ru sk sl sq_al sr sv ta th tr uk zh_cn zh_tw)
          
          qt_add_executable(librecad
          	${SOURCES})
          
          # add constants like M_PI to cmath
          if(WIN32)
              target_compile_definitions(librecad PRIVATE _USE_MATH_DEFINES)
          endif(WIN32)
          
          set_source_files_properties(${FILE} PROPERTIES CPLUSPLUS ON)
          set_source_files_properties(${FILE} PROPERTIES SWIG_FLAGS -builtin)
          swig_add_library(_librecad TYPE USE_BUILD_SHARED_LIBS LANGUAGE python SOURCES ${FILE})
          swig_link_libraries(_librecad Qt6::Core Qt6::Widgets Qt6::Gui Qt6::PrintSupport Qt6::Svg Qt::Network Python3::Python)
          
          #target_link_libraries(librecad PRIVATE Qt6::Core Qt6::Widgets Qt6::Gui Qt6::PrintSupport Qt6::Svg Qt::Network Python3::Python _librecad)
          target_link_libraries(librecad PRIVATE Qt6::Core Qt6::Widgets Qt6::Gui Qt6::PrintSupport Qt6::Svg Qt::Network Python3::Python)
          
          
          #set_target_properties(librecad PROPERTIES
          #	WIN32_EXECUTABLE ON

I’m trying in vain to port my configs.

github.com/emanuel4you/LibreCAD

librecad/src/python.pri

developer

exists( custom.pro ):include( custom.pro )
exists( custom.pri ):include( custom.pri )

TARGET = python

GENERATED_SOURCES += \
    $${TARGET}_wrap.cxx

SWIG_INPUT += \
   $${TARGET}.i

SWIG_INCLUDE += \
    -I$$[QT_INSTALL_HEADERS]

SWIG_OUT_DIR += \
    $${INSTALLDIR}

SWIG_OUT_PYTHON += \
    $${INSTALLDIR}/librecad.py

This file has been truncated. show original

The result is an executable file named “librecad” with the Python module “_librecad” built in (with QtCreator or with make).

When I try this with CMake using swig_add_library(librecad…), I get the message that the target “librecad” already exists. If I specify _librecad in swig_add_library(_librecad) and link “_librecad” with “librecad”, I get the message:

CMakeFiles/librecad.dir/librecad/src/lib/scripting/rs_python.cpp.o: in function RS_Python::RS_Python()': rs_python.cpp:(.text+0x48b4): undefined reference to PyInit__librecad’

because swig now creates __librecad.a, not _librecad.a.

With QtCreator or make, I don’t even have to explicitly link it or set swig to -builtin. It works like this (python.pri).
Please help me.

… __librecad.a /home/emanuel/projects/LibreCAD/.pixi/envs/default/lib/libQt6PrintSupport.so.6.8.2 /home/emanuel/projects/LibreCAD/.pixi/envs/default/lib/libQt6Widgets.so.6.8.2 /home/emanuel/projects/LibreCAD/.pixi/envs/default/lib/libQt6Svg.so.6.8.2 /home/emanuel/projects/LibreCAD/.pixi/envs/default/lib/libQt6Gui.so.6.8.2 /home/emanuel/projects/LibreCAD/.pixi/envs/default/lib/libGL.so /home/emanuel/projects/LibreCAD/.pixi/envs/default/lib/libQt6Network.so.6.8.2 /home/emanuel/projects/LibreCAD/.pixi/envs/default/lib/libQt6Core.so.6.8.2 -pthread /home/emanuel/projects/LibreCAD/.pixi/envs/default/lib/libpython3.13.so && :
/home/emanuel/projects/LibreCAD/.pixi/envs/default/bin/…/lib/gcc/aarch64-conda-linux-gnu/13.3.0/…/…/…/…/aarch64-conda-linux-gnu/bin/ld: CMakeFiles/librecad.dir/librecad/src/lib/scripting/rs_python.cpp.o: in function RS_Python::RS_Python()': rs_python.cpp:(.text+0x48b4): undefined reference to PyInit__librecad’
/home/emanuel/projects/LibreCAD/.pixi/envs/default/bin/…/lib/gcc/aarch64-conda-linux-gnu/13.3.0/…/…/…/…/aarch64-conda-linux-gnu/bin/ld: rs_python.cpp:(.text+0x48b8): undefined reference to `PyInit__librecad’
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.
emanuel@raspberrypi:~/projects/LibreCAD $

emanuel · March 23, 2025, 12:00pm

set_property(TARGET librepython PROPERTY OUTPUT_NAME librecad)

LOL