Similar to the previous recipe, we need to configure a template file, but this time, we will emulate the configure_file() function with a Python script. We keep the CMakeLists.txt largely unchanged, but we replace configure_file(print_info.c.in print_info.c @ONLY) with a set of commands, which we will introduce step by step:

1. First, we construct a variable, _config_script, which will hold a Python script that we will execute a moment later:

set(_config_script
"
from pathlib import Path
source_dir = Path('${CMAKE_CURRENT_SOURCE_DIR}')
binary_dir = Path('${CMAKE_CURRENT_BINARY_DIR}')
input_file = source_dir / 'print_info.c.in'
output_file = binary_dir / 'print_info.c'

import sys
sys.path.insert(0, str(source_dir))

from configurator import configure_file
vars_dict = {
    '_user_name':             '${_user_name}',
    '_host_name':             '${_host_name}',
    '_fqdn':                  '${_fqdn}',
    '_processor_name':        '${_processor_name}',
    '_processor_description': '${_processor_description}',
    '_os_name':               '${_os_name}',
    '_os_release':            '${_os_release}',
    '_os_version':            '${_os_version}',
    '_os_platform':           '${_os_platform}',
    '_configuration_time':    '${_configuration_time}',
    'CMAKE_VERSION':          '${CMAKE_VERSION}',
    'CMAKE_GENERATOR':        '${CMAKE_GENERATOR}',
    'CMAKE_Fortran_COMPILER': '${CMAKE_Fortran_COMPILER}',
    'CMAKE_C_COMPILER':       '${CMAKE_C_COMPILER}',
}
configure_file(input_file, output_file, vars_dict)
")

2. We then use find_package to ensure that the Python interpreter is available for CMake to use:

find_package(PythonInterp QUIET REQUIRED)

3. If the Python interpreter was found, we can execute _config_script from within CMake, to generate the print_info.c file:

execute_process(
  COMMAND
    ${PYTHON_EXECUTABLE} "-c" ${_config_script}
  )

4. After that, we define the executable target and dependencies, but this is unchanged from the previous recipe. Also, the obtained output is unchanged.