Installing

Invoked via the following command (available since 0.47.0):

meson install

or alternatively (on older Meson versions with ninja backend):

ninja install

By default Meson will not install anything. Build targets can be installed by tagging them as installable in the definition.

project('install', 'c')
shared_library('mylib', 'libfile.c', install : true)

There is usually no need to specify install paths or the like. Meson will automatically install it to the standards-conforming location. In this particular case the executable is installed to the bin subdirectory of the install prefix. However if you wish to override the install dir, you can do that with the install_dir argument.

executable('prog', 'prog.c', install : true, install_dir : 'my/special/dir')

Other install commands are the following.

install_headers('header.h', subdir : 'projname') # -> include/projname/header.h
install_man('foo.1') # -> share/man/man1/foo.1
install_data('datafile.dat', install_dir : get_option('datadir') / 'progname')
# -> share/progname/datafile.dat

install_data() supports rename of the file since 0.46.0.

# file.txt -> {datadir}/{projectname}/new-name.txt
install_data('file.txt', rename : 'new-name.txt')

# file1.txt -> share/myapp/dir1/data.txt
# file2.txt -> share/myapp/dir2/data.txt
install_data(['file1.txt', 'file2.txt'],
             rename : ['dir1/data.txt', 'dir2/data.txt'],
             install_dir : 'share/myapp')

Sometimes you want to copy an entire subtree directly. For this use case there is the install_subdir command, which can be used like this.

install_subdir('mydir', install_dir : 'include') # mydir subtree -> include/mydir

Most of the time you want to install files relative to the install prefix. Sometimes you need to go outside of the prefix (such as writing files to /etc instead of /usr/etc. This can be accomplished by giving an absolute install path.

install_data(sources : 'foo.dat', install_dir : '/etc') # -> /etc/foo.dat

Custom install script

Sometimes you need to do more than just install basic targets. Meson makes this easy by allowing you to specify a custom script to execute at install time. As an example, here is a script that generates an empty file in a custom directory.

#!/bin/sh

mkdir "${DESTDIR}/${MESON_INSTALL_PREFIX}/mydir"
touch "${DESTDIR}/${MESON_INSTALL_PREFIX}/mydir/file.dat"

As you can see, Meson sets up some environment variables to help you write your script (DESTDIR is not set by Meson, it is inherited from the outside environment). In addition to the install prefix, Meson also sets the variables MESON_SOURCE_ROOT and MESON_BUILD_ROOT.

Telling Meson to run this script at install time is a one-liner.

meson.add_install_script('myscript.sh')

The argument is the name of the script file relative to the current subdirectory.

Installing as the superuser

When building as a non-root user, but installing to root-owned locations via e.g. sudo ninja install, ninja will attempt to rebuild any out of date targets as root. This results in various bad behaviors due to build outputs and ninja internal files being owned by root.

Running meson install is preferred for several reasons. It can rebuild out of date targets and then re-invoke itself as root. (since 1.1.0) Additionally, running sudo meson install will drop permissions and rebuild out of date targets as the original user, not as root.

(since 1.1.0) Re-invoking as root will try to guess the user's preferred method for re-running commands as root. The order of precedence is: sudo, doas, pkexec (polkit). An elevation tool can be forced by setting $MESON_ROOT_CMD.

DESTDIR support

Sometimes you need to install to a different directory than the install prefix. This is most common when building rpm or deb packages. This is done with the DESTDIR environment variable and it is used just like with other build systems:

$ DESTDIR=/path/to/staging/area meson install

Since 0.57.0 --destdir argument can be used instead of environment. In that case Meson will set DESTDIR into environment when running install scripts.

Since 0.60.0 DESTDIR and --destdir can be a path relative to build directory. An absolute path will be set into environment when executing scripts.

Custom install behaviour

Installation behaviour can be further customized using additional arguments.

For example, if you wish to install the current setup without rebuilding the code (which the default install target always does) and only installing those files that have changed, you would run this command in the build tree:

$ meson install --no-rebuild --only-changed

Installation tags

Since 0.60.0

It is possible to install only a subset of the installable files using meson install --tags tag1,tag2 command line. When --tags is specified, only files that have been tagged with one of the tags are going to be installed.

This is intended to be used by packagers (e.g. distributions) who typically want to split libfoo, libfoo-dev and libfoo-doc packages. Instead of duplicating the list of installed files per category in each packaging system, it can be maintained in a single place, directly in upstream meson.build files.

Meson sets predefined tags on some files. More tags are likely to be added over time, please help extending the list of well known categories.

• devel:
  • static_library(),
  • install_headers(),
  • pkgconfig.generate(),
  • gnome.generate_gir() - .gir file,
  • gnome.generate_vapi() - .vapi file (Since 0.64.0),
  • Files installed into libdir and with .a or .pc extension,
  • File installed into includedir,
  • Generated header files installed with gnome.compile_resources(), gnome.genmarshal(), gnome.mkenums(), gnome.mkenums_simple() and gnome.gdbus_codegen() (Since 0.64.0).
• runtime:
  • executable(),
  • shared_library(),
  • shared_module(),
  • jar(),
  • gnome.compile_resources() - .gresource file (Since 0.64.0),
  • Files installed into bindir,
  • Files installed into libdir and with .so or .dll extension.
• python-runtime:
  • python.install_sources().
• man:
  • install_man().
• doc:
  • gnome.gtkdoc(),
  • gnome.yelp(),
  • hotdoc.generate_doc().
• i18n:
  • i18n.gettext(),
  • qt.compile_translations(),
  • Files installed into localedir.
• typelib:
  • gnome.generate_gir() - .typelib file.
• bin:
  • Scripts and executables bundled with a library meant to be used by end users.
• bin-devel:
  • Scripts and executables bundled with a library meant to be used by developers (i.e. build tools).
• tests:
  • Files installed into installed-tests subdir (Since 0.64.0).
• systemtap:
  • Files installed into systemtap subdir (Since 0.64.0).

Custom installation tag can be set using the install_tag keyword argument on various functions such as custom_target(), configure_file(), install_subdir() and install_data(). See their respective documentation in the reference manual for details. It is recommended to use one of the predefined tags above when possible.

Installable files that have not been tagged either automatically by Meson, or manually using install_tag keyword argument won't be installed when --tags is used. They are reported at the end of <builddir>/meson-logs/meson-log.txt, it is recommended to add missing install_tag to have a tag on each installable files.