# CMAKE_INSTALL_PREFIX

Install directory used by `install()`.

If `make install` is invoked or `INSTALL` is built, this directory is prepended onto all install directories. This variable defaults to `/usr/local` on UNIX and `c:/Program Files/${PROJECT_NAME}` on Windows. See `CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT` for how a project might choose its own default.

On UNIX one can use the `DESTDIR` mechanism in order to relocate the whole installation. `DESTDIR` means DESTination DIRectory. It is commonly used by makefile users in order to install software at non-default location. It is usually invoked like this:

    make DESTDIR=/home/john install

which will install the concerned software using the installation prefix, e.g. `/usr/local` prepended with the `DESTDIR` value which finally gives `/home/john/usr/local`.

WARNING: `DESTDIR` may not be used on Windows because installation prefix usually contains a drive letter like in `C:/Program Files` which cannot be prepended with some other prefix.

The installation prefix is also added to `CMAKE_SYSTEM_PREFIX_PATH` so that `find_package()`, `find_program()`, `find_library()`, `find_path()`, and `find_file()` will search the prefix for other software.

Note

Use the `GNUInstallDirs` module to provide GNU-style options for the layout of directories within the installation.