* check whether the version of libtool.m4 is compatible
with ltconfig/ltmain.sh
-* Inter-library dependencies should be fully tracked by libtool
-and need to work for ltlibraries too. This requires looking up
-installed libtool libraries for transparent support.
-Thomas Tanner has a patch for this.
+* Inter-library dependencies should be fully tracked by libtool and
+need to work for ltlibraries too. This requires looking up installed
+libtool libraries for transparent support. Support for this feature
+is under development, and is expected to be available in libtool 1.4.
* Alexandre Oliva suggests that we should have an option to hardcode
paths into libraries, as well as binaries: `... -Wl,-soname
* Lists of exported symbols should be stored in the pseudo library
so that the size of lt_preloaded_symbols can be reduced.
-* Purpose and usage of convenience libraries must be better documented
-
In the future:
**************
Why return to @code{ar} and @code{ranlib} silliness when you've had a
taste of libtool? Well, sometimes it is desirable to create a static
archive that can never be shared. The most frequent case is when you
-have a ``convenience library'' that is a collection of related object
-files without a really nice interface.
-
-If you create a libtool library (@samp{.la} file) without using the
-@samp{-rpath} flag, then a libtool convenience library is generated.
-You can use these libraries just as if they were libtool object files:
-you can even use them to build other libtool libraries.
-
-If you just want a static convenience library, then you should just
-ignore libtool entirely, and use the old @code{ar} and @code{ranlib}
-commands.
-
-If you want to install a convenience library (but you probably don't),
-then you may use libtool:
+have a set of object files that you use to build several different
+programs. You can create a ``convenience library'' out of those
+objects, and link programs with the library, instead of listing all
+object files for every program. This technique is often used to
+overcome GNU automake's lack of support for linking object files from
+other directories, because it supports linking with libraries from other
+directories.
+
+If you just want to link this convenience library into programs, then
+you could just ignore libtool entirely, and use the old @code{ar} and
+@code{ranlib} commands (or the corresponding GNU automake
+@samp{_LIBRARIES} rules). You can even install a convenience library
+(but you probably don't want to) using libtool:
@example
burger$ @kbd{libtool ./install-sh -c libhello.a /local/lib/libhello.a}
being accidentally stripped (if the installer used the @samp{-s} flag),
as well as automatically running the correct @code{ranlib} command.
+But libtool libraries are more than just collections of object files:
+they can also carry library dependency information, which old archives
+do not. If you want to create a libtool static convenience library, you
+can omit the @samp{-rpath} flag and use @samp{-static} to indicate that
+you're only interested in a static library. When you link a program
+with such a library, libtool will actually link all object files and
+dependency libraries into the program.
+
+If you omit both @samp{-rpath} and @samp{-static}, libtool create a
+libtool convenience library that can be used to create other libtool
+libraries, even shared ones. Just like in the static case, the library
+behaves as an alias to a set of object files and dependency libraries,
+but in this case the object files are suitable for inclusion in shared
+libraries. But be careful not to link a single convenience library,
+directly or indirectly, into a single program or library, otherwise you
+may get errors about symbol redefinitions.
+
+As a rule of thumb, link a libtool convenience library into at most one
+libtool library, and never into a program, and link libtool static
+convenience libraries only into programs, and only if you need to carry
+library dependency information to the user of the static convenience
+library.
+
@cindex standalone binaries
Another common situation where static linking is desirable is in
creating a standalone binary. Use libtool to do the linking and add the
@defmac AC_DISABLE_FAST_INSTALL
Change the default behaviour for @code{AM_PROG_LIBTOOL} to disable
-optimization for fast installation. The user may still override
-this default by specifying @samp{--enable-fast-install}.
+optimization for fast installation. The user may still override this
+default, depending on platform support, by specifying
+@samp{--enable-fast-install}.
@end defmac
@defmac AC_DISABLE_SHARED
AC_LIBTOOL_DLOPEN
dnl Configure libtool
AM_PROG_LIBTOOL
-dnl Enable building of the convenience library and set LIBLTDL accordingly
+dnl Enable building of the convenience library
+dnl and set LIBLTDL accordingly
AC_LIBLTDL_CONVENIENCE
dnl Substitute LIBLTDL in the Makefiles
AC_SUBST(LIBLTDL)
Flag to hardcode a @var{libdir} variable into a binary, so that the
dynamic linker searches @var{libdir} for shared libraries at runtime.
If it is empty, libtool will try to use some other hardcoding mechanism.
-If everything else fails, it will fallback to
-@samp{hardcode_action=relink}.
@end defvar
@defvar hardcode_libdir_separator
projects / thirdparty / libtool.git / commitdiff
