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

    add_custom_target(doc
        COMMAND ${DOXYGEN_EXECUTABLE} ${doxyfile}
        WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
        COMMENT "Generating API documentation with Doxygen"
        VERBATIM)

endif()