# option ALL allows to build the docs together with the code
add_custom_target( doc_doxygen ALL
COMMAND ${DOXYGEN_EXECUTABLE}${DOXYGEN_IN}
WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})# WORKING_DIRECTORY: Execute the command with the given current working directory. If it is a relative path it will be interpreted relative to the build tree directory corresponding to the current source directory.
WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
else()
message("Doxygen need to be installed to generate the doxygen documentation")