Pybind11 CMakeLists

[petrasvestartas]

Hi,

I wish there would be more examples files on documentation. Specially for CMake. Here is one, made with some trial and errors.
Hopefully this will save somebody some time of work. If you see better approaches please let me know.
I am using Windows 10.

CMake

Pybind11 can be downloaded using this command directly in CMake:

########################################################################
# PYBIND11
######################################################################## 

ExternalProject_Add(pybind11
  URL https://github.com/pybind/pybind11/archive/refs/tags/v2.10.3.zip
  CMAKE_ARGS
    -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}
    -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}
  SOURCE_DIR   "${CMAKE_BINARY_DIR}/install/pybind11"
  BUILD_ALWAYS "" #do not buld
  INSTALL_COMMAND "" #installer for now is empty
)

The pybind11 needs to be configured like this, pay a special attention to how Python is found and pybind11_add_module function:

  ###############################################################################
  # WRAPPER LIBRARY FOR PYBIND11
  # PYBIND11 - requires python installation besides the python11
  # WARNING - your conda environment must not have the module with the same name installed, 
  # SOLUTION - check by "conda list" and "pip uninstall compas_wood"
  ###############################################################################

  #set a few properties
  set(CMAKE_EXPORT_COMPILE_COMMANDS 1)
  set(PYTHON_MODULE_NAME "wood_pybind11")

  # find python do not use find_package(Python) this would fail if a few python versions are installed, better to use one from Anaconda
  find_package(Python 3.6 REQUIRED COMPONENTS Interpreter Development ${_pybind11_quiet}) 

  # add pybind11 to enable CMake command: pybind11_add_module
  add_subdirectory("${CMAKE_BINARY_DIR}/install/pybind11")

  # module - this is a special cmake command from the pybind11 package
  pybind11_add_module (
    "${PYTHON_MODULE_NAME}" # name of the module
    "${CMAKE_SOURCE_DIR}/src/compas_wood/include/compas_wood.cpp"
  )

  # include directories for header files
  target_include_directories(
    "${PYTHON_MODULE_NAME}" # name of the module
    PRIVATE "${CMAKE_BINARY_DIR}/install/pybind11/"
    PRIVATE "${CMAKE_SOURCE_DIR}/src/compas_wood/include/"
  )

  # include static libraries
  target_link_libraries(
    "${PYTHON_MODULE_NAME}" 
  )

C++

compas_wood.cpp file

#include "compas_wood.h"

void test()
{
    printf("\n________________________________________________________________________\n");
    printf("\n_______________________Hello from CPP Wood______________________________\n");
    printf("\n___If you see this message, say hi to the developer Petras Vestartas ___\n");
    printf("\n[email protected]___________________________\n");
    printf("\n________________________________________________________________________\n");
}

PYBIND11_MODULE(wood_pybind11, m)
{
    m.doc() = "optional module docstring"; 
    m.def("test", &test); // Function reference
}

compas_wood.h file

#include <pybind11/pybind11.h>
namespace py = pybind11;

void test();

Python

python file (I had to add a directory where the "wood_pybind11.cp38-win_amd64.pyd" is and tested the basic function ):

####################################################################################################################################
# Link the python module compiled in the release folder
####################################################################################################################################
import os.path as path
import sys
module_folder = path.abspath(path.join(__file__, "../../../..")) + "\\build_win\\Release"
print(module_folder)
sys.path.append(module_folder)

####################################################################################################################################
# Import the wood_pybind11 module
####################################################################################################################################
import wood_pybind11
wood_pybind11.test()

Output

________________________________________________________________________

_______________________Hello from CPP Wood______________________________

___If you see this message, say hi to the developer Petras Vestartas ___

[email protected]___________________________

🍻🍻🍻

[Dariusz1989]

Thanks for helper!
Also, you can try using chatgpt for boilerplate/etc.
Its been saving me days lately.