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(automake.info)A Shared Library

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Building a Shared Library
=========================

   Building shared libraries is a relatively complex matter.  For this
reason, GNU Libtool (Note: Introduction.) was created to
help build shared libraries in a platform-independent way.

   Automake uses Libtool to build libraries declared with the
`LTLIBRARIES' primary.  Each `_LTLIBRARIES' variable is a list of
shared libraries to build.  For instance, to create a library named
`libgettext.a' and its corresponding shared libraries, and install them
in `libdir', write:

     lib_LTLIBRARIES = libgettext.la

   Note that shared libraries _must_ be installed, so
`check_LTLIBRARIES' is not allowed.  However, `noinst_LTLIBRARIES' is
allowed.  This feature should be used for libtool "convenience
libraries".

   For each library, the `LIBRARY_LIBADD' variable contains the names
of extra libtool objects (`.lo' files) to add to the shared library.
The `LIBRARY_LDFLAGS' variable contains any additional libtool flags,
such as `-version-info' or `-static'.

   Where an ordinary library might include `@LIBOBJS@', a libtool
library must use `@LTLIBOBJS@'.  This is required because the object
files that libtool operates on do not necessarily end in `.o'.  The
libtool manual contains more details on this topic.

   For libraries installed in some directory, Automake will
automatically supply the appropriate `-rpath' option.  However, for
libraries determined at configure time (and thus mentioned in
`EXTRA_LTLIBRARIES'), Automake does not know the eventual installation
directory; for such libraries you must add the `-rpath' option to the
appropriate `_LDFLAGS' variable by hand.

   Note: Using Automake with Libtool, for more
information.