1CPACK_CUSTOM_INSTALL_VARIABLES 2------------------------------ 3 4.. versionadded:: 3.21 5 6CPack variables (set via e.g. ``cpack -D``, ``CPackConfig.cmake`` or 7:variable:`CPACK_PROJECT_CONFIG_FILE` scripts) are not directly visible in 8installation scripts. Instead, one can pass a list of ``varName=value`` 9pairs in the ``CPACK_CUSTOM_INSTALL_VARIABLES`` variable. At install time, 10each list item will result in a variable of the specified name (``varName``) 11being set to the given ``value``. The ``=`` can be omitted for an empty 12``value``. 13 14``CPACK_CUSTOM_INSTALL_VARIABLES`` allows the packaging installation to be 15influenced by the user or driving script at CPack runtime without having to 16regenerate the install scripts. 17 18Example 19""""""" 20 21.. code-block:: cmake 22 23 install(FILES large.txt DESTINATION data) 24 25 install(CODE [[ 26 if(ENABLE_COMPRESSION) 27 # "run-compressor" is a fictional tool that produces 28 # large.txt.xz from large.txt and then removes the input file 29 execute_process(COMMAND run-compressor $ENV{DESTDIR}${CMAKE_INSTALL_PREFIX}/large.txt) 30 endif() 31 ]]) 32 33With the above example snippet, :manual:`cpack <cpack(1)>` will by default 34run the installation script with ``ENABLE_COMPRESSION`` unset, resulting in 35a package containing the uncompressed ``large.txt``. This can be overridden 36when invoking :manual:`cpack <cpack(1)>` like so: 37 38.. code-block:: shell 39 40 cpack -D "CPACK_CUSTOM_INSTALL_VARIABLES=ENABLE_COMPRESSION=TRUE" 41 42The installation script will then run with ``ENABLE_COMPRESSION`` set to 43``TRUE``, resulting in a package containing the compressed ``large.txt.xz`` 44instead. 45