What install command does in cmake?

Question

I am sorry for being so naive. I tried to understand from this cmake website's link But could not understand. I have a sample cmake file, where an executable is generated by

add_executable(${PROJECT_NAME}_node src/filename.cpp)

Then later it installed by the following command

install(TARGETS ${PROJECT_NAME}_node ${PROJECT_NAME}
ARCHIVE DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}
LIBRARY DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}
RUNTIME DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION} )

This cmake is from ROS so catkin is there. The overall question remains the same. Does someone know, why do we need to install TARGETS/ FILES?

Answer 1

INSTALL is useful in, at least, two scenarios:

• You download some package's source code, generate the binaries, which you want to use in your system. You can INSTALL them under /usr/bin, for example

• You compile some library which you'll use from another product. It will gather the required files (header files, libraries...), and just those, and put them in a known place, no matter where the library compilation expects them.

You could just copy them, but relying on CMake allows the process to be expressed at a higher level.