find_package(Doxygen)
if (DOXYGEN_FOUND)
  configure_file(
    ${CMAKE_CURRENT_SOURCE_DIR}/Doxyfile.in
    ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile
    @ONLY
    )

  # note the option ALL which allows to build the docs together with the application
  add_custom_target(doc
    COMMAND ${DOXYGEN_EXECUTABLE} ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile
    WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
    COMMENT "Generating API documentation with Doxygen"
    VERBATIM
    )
else (DOXYGEN_FOUND)
  message("Doxygen need to be installed to generate the doxygen documentation")
endif (DOXYGEN_FOUND)