[CMake] Return an Error Code (or something) from a CMake Script.

[Michael Jackson]

In our CMake based project I generate a *.cmake file which I call with the following bit of code:

  add_custom_target(DREAM3D_MKDOCS_GENERATION ALL
    COMMAND "${CMAKE_COMMAND}" -P "${docsCmakeFile}"    
    COMMENT "using mkdocs to generate the documentation"
  )

Inside the generated file is the following cmake command:

  message(STATUS "Starting mkdocs execution. This can take a while.....")
  execute_process(COMMAND "/path/to/mkdocs" build
                OUTPUT_VARIABLE mkdocs_gen_output
                RESULT_VARIABLE mkdocs_gen_result
                ERROR_VARIABLE mkdocs_gen_error
                WORKING_DIRECTORY "/Users/mjackson/DREAM3D-Dev/DREAM3D-Build/Debug/Documentation/mkdocs"
                )
  message(STATUS "mkdocs_gen_result: ${mkdocs_gen_result}")
  message(STATUS "mkdocs_gen_error: ${mkdocs_gen_error}")
  message(STATUS "**************************************************************************")
  message(STATUS "mkdocs_gen_output: ${mkdocs_gen_output}")
  message(STATUS "**************************************************************************")


The issue that I am having is that if the mkdocs command fails, the build does NOT show the failure. Is there a way to have the "cmake -P" command pick up the fact that the cmake script failed so that the build fails or throws a warning/error?

Thanks
Mike Jackson