1CPACK_SET_DESTDIR
2-----------------
3
4Boolean toggle to make CPack use ``DESTDIR`` mechanism when packaging.
5
6``DESTDIR`` means DESTination DIRectory.  It is commonly used by makefile
7users in order to install software at non-default location.  It is a
8basic relocation mechanism that should not be used on Windows (see
9:variable:`CMAKE_INSTALL_PREFIX` documentation).  It is usually invoked like
10this:
11
12::
13
14 make DESTDIR=/home/john install
15
16which will install the concerned software using the installation
17prefix, e.g. ``/usr/local`` prepended with the ``DESTDIR`` value which
18finally gives ``/home/john/usr/local``.  When preparing a package, CPack
19first installs the items to be packaged in a local (to the build tree)
20directory by using the same ``DESTDIR`` mechanism.  Nevertheless, if
21``CPACK_SET_DESTDIR`` is set then CPack will set ``DESTDIR`` before doing the
22local install.  The most noticeable difference is that without
23``CPACK_SET_DESTDIR``, CPack uses :variable:`CPACK_PACKAGING_INSTALL_PREFIX`
24as a prefix whereas with ``CPACK_SET_DESTDIR`` set, CPack will use
25:variable:`CMAKE_INSTALL_PREFIX` as a prefix.
26
27Manually setting ``CPACK_SET_DESTDIR`` may help (or simply be necessary)
28if some install rules uses absolute ``DESTINATION`` (see CMake
29:command:`install` command).  However, starting with CPack/CMake 2.8.3 RPM
30and DEB installers tries to handle ``DESTDIR`` automatically so that it is
31seldom necessary for the user to set it.
32