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Annotation of embedaddon/libiconv/doc/relocatable.texi, revision 1.1.1.2

1.1       misho       1: @node Enabling Relocatability
                      2: @section Enabling Relocatability
                      3: 
                      4: It has been a pain for many users of GNU packages for a long time that
                      5: packages are not relocatable.  It means a user cannot copy a program,
                      6: installed by another user on the same machine, to his home directory,
                      7: and have it work correctly (including i18n).  So many users need to go
                      8: through @code{configure; make; make install} with all its
                      9: dependencies, options, and hurdles.
                     10: 
                     11: Red Hat, Debian, and similar package systems solve the ``ease of
                     12: installation'' problem, but they hardwire path names, usually to
                     13: @file{/usr} or @file{/usr/local}.  This means that users need root
                     14: privileges to install a binary package, and prevents installing two
                     15: different versions of the same binary package.
                     16: 
                     17: A relocatable program can be moved or copied to a different location
1.1.1.2 ! misho      18: on the file system.  It is possible to make symlinks to the installed
1.1       misho      19: and moved programs, and invoke them through the symlink. It is
                     20: possible to do the same thing with a hard link @emph{only} if the hard
                     21: link file is in the same directory as the real program.
                     22: 
                     23: To configure a program to be relocatable, add
                     24: @option{--enable-relocatable} to the @command{configure} command line.
                     25: 
                     26: On some OSes the executables remember the location of shared libraries
                     27: and prefer them over any other search path.  Therefore, such an
                     28: executable will look for its shared libraries first in the original
                     29: installation directory and only then in the current installation
                     30: directory.  Thus, for reliability, it is best to also give a
                     31: @option{--prefix} option pointing to a directory that does not exist
                     32: now and which never will be created, e.g.@:
                     33: @option{--prefix=/nonexistent}.  You may use
                     34: @code{DESTDIR=@var{dest-dir}} on the @command{make} command line to
                     35: avoid installing into that directory.
                     36: 
                     37: We do not recommend using a prefix writable by unprivileged users
                     38: (e.g.@: @file{/tmp/inst$$}) because such a directory can be recreated
                     39: by an unprivileged user after the original directory has been removed.
                     40: We also do not recommend prefixes that might be behind an automounter
                     41: (e.g.@: @file{$HOME/inst$$}) because of the performance impact of
                     42: directory searching.
                     43: 
                     44: Here's a sample installation run that takes into account all these
                     45: recommendations:
                     46: 
                     47: @example
                     48: ./configure --enable-relocatable --prefix=/nonexistent
                     49: make
                     50: make install DESTDIR=/tmp/inst$$
                     51: @end example
                     52: 
                     53: Installation with @option{--enable-relocatable} will not work for
                     54: setuid or setgid executables, because such executables search only
                     55: system library paths for security reasons.  Also, installation with
                     56: @option{--enable-relocatable} might not work on OpenBSD, when the
                     57: package contains shared libraries and libtool versions 1.5.xx are used.
                     58: 
                     59: The runtime penalty and size penalty are negligible on GNU/Linux (just
                     60: one system call more when an executable is launched), and small on
                     61: other systems (the wrapper program just sets an environment variable
                     62: and executes the real program).