上QQ阅读APP看书，第一时间看更新

How to do it

We will build up the CMakeLists.txt file step by step:

We start out by defining the minimum CMake version and project name. Note that for this example we will not need any language support:

cmake_minimum_required(VERSION 3.5 FATAL_ERROR)

project(recipe-01 LANGUAGES NONE)

Then, we use the find_package command to find the Python interpreter:

find_package(PythonInterp REQUIRED)

Then, we execute a Python command and capture its output and return value:

execute_process(
  COMMAND
    ${PYTHON_EXECUTABLE} "-c" "print('Hello, world!')"
  RESULT_VARIABLE _status
  OUTPUT_VARIABLE _hello_world
  ERROR_QUIET
  OUTPUT_STRIP_TRAILING_WHITESPACE
  )

Finally, we print the return value and the output of the Python command:

message(STATUS "RESULT_VARIABLE is: ${_status}")
message(STATUS "OUTPUT_VARIABLE is: ${_hello_world}")

Now, we can examine the output of the configuration step:

$ mkdir -p build
$ cd build
$ cmake ..

-- Found PythonInterp: /usr/bin/python (found version "3.6.5") 
-- RESULT_VARIABLE is: 0
-- OUTPUT_VARIABLE is: Hello, world!
-- Configuring done
-- Generating done
-- Build files have been written to: /home/user/cmake-cookbook/chapter-03/recipe-01/example/build