File: make.info,  Node: DESTDIR,  Next: Directory Variables,  Prev: Command Variables,  Up: Makefile Conventions

16.4 'DESTDIR': Support for Staged Installs
===========================================

'DESTDIR' is a variable prepended to each installed target file, like
this:

     $(INSTALL_PROGRAM) foo $(DESTDIR)$(bindir)/foo
     $(INSTALL_DATA) libfoo.a $(DESTDIR)$(libdir)/libfoo.a

   The 'DESTDIR' variable is specified by the user on the 'make' command
line as an absolute file name.  For example:

     make DESTDIR=/tmp/stage install

'DESTDIR' should be supported only in the 'install*' and 'uninstall*'
targets, as those are the only targets where it is useful.

   If your installation step would normally install '/usr/local/bin/foo'
and '/usr/local/lib/libfoo.a', then an installation invoked as in the
example above would install '/tmp/stage/usr/local/bin/foo' and
'/tmp/stage/usr/local/lib/libfoo.a' instead.

   Prepending the variable 'DESTDIR' to each target in this way provides
for "staged installs", where the installed files are not placed directly
into their expected location but are instead copied into a temporary
location ('DESTDIR').  However, installed files maintain their relative
directory structure and any embedded file names will not be modified.

   You should not set the value of 'DESTDIR' in your 'Makefile' at all;
then the files are installed into their expected locations by default.
Also, specifying 'DESTDIR' should not change the operation of the
software in any way, so its value should not be included in any file
contents.

   'DESTDIR' support is commonly used in package creation.  It is also
helpful to users who want to understand what a given package will
install where, and to allow users who don't normally have permissions to
install into protected areas to build and install before gaining those
permissions.  Finally, it can be useful with tools such as 'stow', where
code is installed in one place but made to appear to be installed
somewhere else using symbolic links or special mount operations.  So, we
strongly recommend GNU packages support 'DESTDIR', though it is not an
absolute requirement.