13. What Gets Installed

13.1 Basics of installation

Naturally, Automake handles the details of actually installing your program once it has been built. All files named by the various primaries are automatically installed in the appropriate places when the user runs make install.

A file named in a primary is installed by copying the built file into the appropriate directory. The base name of the file is used when installing.

bin_PROGRAMS = hello subdir/goodbye

In this example, both `hello' and `goodbye' will be installed in $(bindir).

Sometimes it is useful to avoid the basename step at install time. For instance, you might have a number of header files in subdirectories of the source tree which are laid out precisely how you want to install them. In this situation you can use the `nobase_' prefix to suppress the base name step. For example:

nobase_include_HEADERS = stdio.h sys/types.h

Will install `stdio.h' in $(includedir) and `types.h' in $(includedir)/sys.

13.2 The two parts of install

Automake generates separate install-data and install-exec targets, in case the installer is installing on multiple machines which share directory structure--these targets allow the machine-independent parts to be installed only once. install-exec installs platform-dependent files, and install-data installs platform-independent files. The install target depends on both of these targets. While Automake tries to automatically segregate objects into the correct category, the `Makefile.am' author is, in the end, responsible for making sure this is done correctly.

Variables using the standard directory prefixes `data', `info', `man', `include', `oldinclude', `pkgdata', or `pkginclude' (e.g. `data_DATA') are installed by `install-data'.

Variables using the standard directory prefixes `bin', `sbin', `libexec', `sysconf', `localstate', `lib', or `pkglib' (e.g. `bin_PROGRAMS') are installed by `install-exec'.

Any variable using a user-defined directory prefix with `exec' in the name (e.g. `myexecbin_PROGRAMS' is installed by `install-exec'. All other user-defined prefixes are installed by `install-data'.

13.3 Extending installation

It is possible to extend this mechanism by defining an install-exec-local or install-data-local target. If these targets exist, they will be run at `make install' time. These rules can do almost anything; care is required.

Automake also supports two install hooks, install-exec-hook and install-data-hook. These hooks are run after all other install rules of the appropriate type, exec or data, have completed. So, for instance, it is possible to perform post-installation modifications using an install hook.

13.4 Staged installs

Automake generates support for the `DESTDIR' variable in all install rules. `DESTDIR' is used during the `make install' step to relocate install objects into a staging area. Each object and path is prefixed with the value of `DESTDIR' before being copied into the install area. Here is an example of typical DESTDIR usage:

make DESTDIR=/tmp/staging install

This places install objects in a directory tree built under `/tmp/staging'. If `/gnu/bin/foo' and `/gnu/share/aclocal/foo.m4' are to be installed, the above command would install `/tmp/staging/gnu/bin/foo' and `/tmp/staging/gnu/share/aclocal/foo.m4'.

This feature is commonly used to build install images and packages. For more information, see section `Makefile Conventions' in The GNU Coding Standards.

Support for `DESTDIR' is implemented by coding it directly into the install rules. If your `Makefile.am' uses a local install rule (e.g., install-exec-local) or an install hook, then you must write that code to repsect `DESTDIR'.

13.5 Rules for the user

Automake also generates an uninstall target, an installdirs target, and an install-strip target.

Automake supports uninstall-local and uninstall-hook. There is no notion of separate uninstalls for "exec" and "data", as that does not make sense.

Note that uninstall is not meant as a replacement for a real packaging tool.