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* TODO: libltdl is now documented

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* doc/libltdl.texi (linking with installed libtool libraries):
  fixed typo
* doc/libltdl.texi (libltdl): added documentation for building
  libtool modules and examples how to embed libltdl
* ltmain.in: don't ignore user-specified run-paths (fixed it
  at the right place)
This commit is contained in:
Thomas Tanner 1999-03-14 11:18:37 +00:00
parent d4d597e0ed
commit 7378519a1b
4 changed files with 140 additions and 42 deletions
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10
ChangeLog
View File

@ -1,3 +1,13 @@
1999-03-14 Thomas Tanner <tanner@gmx.de>
* TODO: libltdl is now documented
* doc/libltdl.texi (linking with installed libtool libraries):
fixed typo
* doc/libltdl.texi (libltdl): added documentation for building
libtool modules and examples how to embed libltdl
* ltmain.in: don't ignore user-specified run-paths (fixed it
at the right place)
1999-03-14 Alexandre Oliva <oliva@dcc.unicamp.br>
* ltmain.in (deplibs_check_method=none): discard -L and -R

2
TODO
View File

@ -20,8 +20,6 @@ so that the size of lt_preloaded_symbols can be reduced.
* Documentation:
- libltdl documentation needs to be completed.
- AC_PROG_LIBTOOL, AC_ENABLE/DISABLE_SHARED/STATIC/FAST_INSTALL,
AC_LIBTOOL_DLOPEN, AC_LIBLTDL_CONVENIENCE/INSTALLABLE are not documented

117
doc/libtool.texi
View File

@ -710,7 +710,7 @@ Thing (TM) for you:
@example
burger$ @kbd{libtool gcc -g -O -o test test.o /usr/local/lib/libhello.la}
gcc -g -O -o @value{objdir}/test test.o -Wl,--rpath
-Wl,/usr/local/lib /usr/local/lib/libhello.la -lm
-Wl,/usr/local/lib /usr/local/lib/libhello.a -lm
creating test
burger$
@end example
@ -2768,11 +2768,68 @@ any libltdl function other than @code{lt_dlpreopen_default} or the macro
@node Modules for libltdl
@section Creating modules that can be @code{dlopen}ed
You just have to link the module with libtool's @samp{-module} switch,
and link any program that is intended to dlopen the module with
@samp{-dlopen modname.la}. If the module depends on any other
libraries, make sure you specify them either when you link the module or
when you link programs that dlopen it.
Libtool modules are like normal libtool libraries with a few exceptions:
You have to link the module with libtool's @samp{-module} switch,
and you should link any program that is intended to dlopen the module with
@samp{-dlopen modulename.la} so that libtool can dlpreopen the module
on platforms which don't support dlopening. If the module depends on any
other libraries, make sure you specify them either when you link the module
or when you link programs that dlopen it.
If you want to disable @pxref{Versioning} for a specific module
you should link it with the @samp{-avoid-version} switch.
Note that libtool modules don't need to have a "lib" prefix.
However, automake 1.4 or higher is required to build such modules.
Usually a set of modules provide the same interface, i.e, exports the same
symbols, so that a program can dlopen them without having to know more
about their internals.
In order to avoid symbol conflicts all exported symbols must be prefixed
with "modulename_LTX_" (@samp{modulename} is the name of the module).
Internal symbols must be named in such a way that they won't conflict
with other modules, for example, by prefixing them with "_modulename_".
Although some platforms support having the same symbols defined more than
once it is generally not portable and it makes it impossible to dlpreopen
such modules. libltdl will automatically cut the prefix off to get
the real name of the symbol. Additionally, it supports modules which
don't use a prefix so that you can also dlopen non-libtool modules.
@file{foo1.c} gives an example of a portable libtool module.
Exported symbols are prefixed with "foo1_LTX_", internal symbols
with "_foo1_". Aliases are defined at the beginning so that the code
is more readable.
@example
/* aliases for the exported symbols */
#define foo foo1_LTX_foo
#define bar foo1_LTX_bar
/* a global variable definition */
int bar = 1;
/* a private function */
int _foo1_helper() @{
return bar;
@}
/* an exported function */
int foo() @{
return _foo_helper();
@}
@end example
@noindent
The @file{Makefile.am} contains the necessary rules to build the
module @file{foo1.la}:
@example
...
lib_LTLIBRARIES = foo1.la
foo1_la_SOURCES = foo1.c
foo1_la_LDFLAGS = -module
...
@end example
@node Distributing libltdl
@section How to distribute libltdl with your package
@ -2786,12 +2843,17 @@ convenience library or an installable libtool library.
One advantage of the convenience library is that it is not installed, so
the fact that you use libltdl will not be apparent to the user, and it
will not overwrite a pre-installed version of libltdl a user might have.
On the other hand, if you want to upgrade libltdl for any reason
(e.g. a bugfix) you'll have to recompile your package instead of just
replacing an installed version of libltdl.
However, if your programs or libraries are linked with other libraries
that use such a pre-installed version of libltdl, you may get linker
errors or run-time crashes. Another problem is that you cannot link the
convenience library into more than one libtool library, then link a
single program with these libraries, because you may get duplicate
symbols. In order to enable this flavor of libltdl, you should add the
symbols. In general you can safely use the convenience library in programs
which don't depend on other libraries that might use libltdl too.
In order to enable this flavor of libltdl, you should add the
line @samp{AC_LIBLTDL_CONVENIENCE} to your @file{configure.in},
@emph{after} @samp{AM_PROG_LIBTOOL}.
@ -2805,6 +2867,13 @@ the test and determine that the libltdl embedded must be installed,
regardless of the existence of another version, using the configure
switch @samp{--enable-ltdl-install}.
In order to embed libltdl into your package, just add @samp{--ltdl} to
the @code{libtoolize} command line. It will copy the libltdl sources
to a subdirectory @samp{libltdl} in your package.
Both macros accept an optional argument to specify the location
of the @samp{libltdl} directory. By the default both macros assume that it
is @samp{$@{top_builddir@}/libltdl}.
Whatever macro you use, it is up to you to ensure that your
@file{configure.in} will configure libltdl, using
@samp{AC_CONFIG_SUBDIRS}, and that your @file{Makefile}s will start
@ -2831,8 +2900,38 @@ Avoid using the @code{-all-static} switch when linking programs with
libltdl; this will not work on all plaforms, because the dlopening
functions may not be available for static linking.
In order to embed libltdl into your package, just add @samp{--ltdl} to
the @code{libtoolize} command line.
The following example shows you how to embed the convenience libltdl
in your package. In order to use the installable variant just replace
AC_LIBLTDL_CONVENIENCE with AC_LIBLTDL_INSTALLABLE. We assume that
libltdl was embedded using @samp{libtoolize --ltdl}.
configure.in:
@example
...
dnl Check for dlopen support
AC_LIBTOOL_DLOPEN
dnl Configure libtool
AM_PROG_LIBTOOL
dnl Enable building of the convenience library and set LIBLTDL accordingly
AC_LIBLTDL_CONVENIENCE
dnl Substitute LIBLTDL in the Makefiles
AC_SUBST(LIBLTDL)
dnl Configure libltdl
AC_CONFIG_SUBDIRS(libltdl)
...
@end example
Makefile.am:
@example
...
SUBDIRS = libltdl
myprog_LDFLAGS = -export-dynamic
# The quotes around -dlopen below fool automake into accepting it
myprog_LDADD = $(LIBLTDL) "-dlopen" self "-dlopen" libfoo.la
myprog_DEPENDENCIES = $(LIBLTDL) libfoo.la
...
@end example
@node Other languages
@chapter Using libtool with other languages

53
ltmain.in
View File

@ -800,6 +800,7 @@ compiler."
fi
# now prepend the system-specific ones
eval lib_search_path=\"$sys_lib_search_path_spec\$lib_search_path\"
eval sys_lib_dlsearch_path=\"$sys_lib_dlsearch_path_spec\"
avoid_version=no
dlfiles=
@ -1240,14 +1241,27 @@ compiler."
esac
# This is the magic to use -rpath.
case "$compile_rpath " in
*" $absdir "*) ;;
*) compile_rpath="$compile_rpath $absdir" ;;
esac
case "$finalize_rpath " in
*" $libdir "*) ;;
*) finalize_rpath="$finalize_rpath $libdir" ;;
esac
# Skip directories that are in the system default run-time
# search path, unless they have been requested with -R.
case " $sys_lib_dlsearch_path " in
*" $absdir "*) ;;
*)
case "$compile_rpath " in
*" $absdir "*) ;;
*) compile_rpath="$compile_rpath $absdir"
esac
;;
esac
case " $sys_lib_dlsearch_path " in
*" $libdir "*) ;;
*)
case "$finalize_rpath " in
*" $libdir "*) ;;
*) finalize_rpath="$finalize_rpath $libdir"
esac
;;
esac
lib_linked=yes
case "$hardcode_action" in
@ -2174,21 +2188,9 @@ EOF
fi
# Now hardcode the library paths
eval sys_lib_dlsearch_path=\"$sys_lib_dlsearch_path_spec\"
rpath=
hardcode_libdirs=
for libdir in $compile_rpath $finalize_rpath; do
# Skip directories that are in the system default run-time
# search path, unless they have been requested with -R.
case " $sys_lib_dlsearch_path " in
*" $libdir "*)
case " $xrpath " in
*" $libdir "*) ;;
*) continue ;;
esac ;;
*) ;;
esac
if test -n "$hardcode_libdir_flag_spec"; then
if test -n "$hardcode_libdir_separator"; then
if test -z "$hardcode_libdirs"; then
@ -2226,17 +2228,6 @@ EOF
rpath=
hardcode_libdirs=
for libdir in $finalize_rpath; do
# Skip directories that are in the system default run-time
# search path, unless they have been requested with -R.
case " $sys_lib_dlsearch_path " in
*" $libdir "*)
case " $xrpath " in
*" $libdir "*) ;;
*) continue ;;
esac ;;
*) ;;
esac
if test -n "$hardcode_libdir_flag_spec"; then
if test -n "$hardcode_libdir_separator"; then
if test -z "$hardcode_libdirs"; then