Thinking even more, "ld-version-script" seems like a better module name,
to avoid confusion with any other non-LD "version" scripts.
The patch below also makes the visibility.texi be part of the gnulib
manual. I assume this was just a mistake and not intentional?
I have pushed the patch below, but I still would appreciate more review
and discussion of it.
/Simon
>From 5d412172ab1a1775153957a47dc397ce26caf90c Mon Sep 17 00:00:00 2001
From: Simon Josefsson <si...@josefsson.org>
Date: Tue, 3 Mar 2009 12:00:59 +0100
Subject: [PATCH] Add new module ld-version-script. Fix doc for visibility.
---
ChangeLog | 9 +++++
doc/gnulib.texi | 6 +++
doc/ld-version-script.texi | 77 ++++++++++++++++++++++++++++++++++++++++++++
doc/visibility.texi | 3 ++
m4/ld-version-script.m4 | 39 ++++++++++++++++++++++
modules/ld-version-script | 14 ++++++++
6 files changed, 148 insertions(+), 0 deletions(-)
create mode 100644 doc/ld-version-script.texi
create mode 100644 m4/ld-version-script.m4
create mode 100644 modules/ld-version-script
diff --git a/ChangeLog b/ChangeLog
index b3e2b3b..796cd5e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2009-03-03 Simon Josefsson <si...@josefsson.org>
+
+ * doc/gnulib.texi: Link to sections for ld version script and
+ visibility.
+ * doc/visibility.texi: Add @node and @section.
+ * modules/ld-version-script: New module.
+ * m4/ld-version-script.m4: New file.
+ * doc/ld-version-script.texi: New file.
+
2009-03-02 David Lutterkort <lut...@redhat.com>
* lib/safe-alloc.h (__GNUC_PREREQ): New macro.
diff --git a/doc/gnulib.texi b/doc/gnulib.texi
index d2a3a13..ceb0335 100644
--- a/doc/gnulib.texi
+++ b/doc/gnulib.texi
@@ -5825,6 +5825,8 @@ This list of functions is sorted according to the header
that declares them.
* func::
* warnings::
* manywarnings::
+* visibility::
+* LD Version Scripts::
@end menu
@node alloca
@@ -5917,6 +5919,10 @@ generated automatically.
@include manywarnings.texi
+...@include visibility.texi
+
+...@include ld-version-script.texi
+
@node GNU Free Documentation License
@appendix GNU Free Documentation License
diff --git a/doc/ld-version-script.texi b/doc/ld-version-script.texi
new file mode 100644
index 0000000..8582edf
--- /dev/null
+++ b/doc/ld-version-script.texi
@@ -0,0 +1,77 @@
+...@node LD Version Scripts
+...@section LD Version Scripts
+
+The @code{ld-version-script} module can be used to add shared library
+versioning support. Currently, only GNU LD and the Solaris linker
+supports this.
+
+Version scripts provides information that can be used by GNU/Linux
+distribution packaging tools. For example, Debian has a tool
+...@code{dpkg-shlibdeps} that can determine the minimal required version
+of each dependency (by looking at the symbol list) and stuff the
+information into the Debian specific packaging files.
+
+For more information and other uses of version scripts, see Ulrich
+Drepper's paper @url{http://people.redhat.com/drepper/dsohowto.pdf}
+
+You use the module by importing it to your library, and then add the
+following lines to the @code{Makefile.am} that builds the library:
+
+...@smallexample
+if HAVE_LD_VERSION_SCRIPT
+libfoo_la_LDFLAGS += -Wl,--version-script=$(srcdir)/libfoo.map
+endif
+...@end smallexample
+
+The version script file format is documented in the GNU LD manual, but
+a small example would be:
+
+...@smallexample
+LIBFOO_1.0 @{
+ global:
+ libfoo_init; libfoo_doit; libfoo_done;
+
+ local:
+ *;
+...@};
+...@end smallexample
+
+If you target platforms that do not support linker scripts (i.e., all
+platforms that doesn't use GNU LD) you may want to consider a more
+portable but less powerful alternative: libtool
+...@code{-export-symbols}. It will hide internal symbols from your
+library, but will not add ELF versioning symbols. Your usage would
+then be something like:
+
+...@smallexample
+if HAVE_LD_VERSION_SCRIPT
+libfoo_la_LDFLAGS += -Wl,--version-script=$(srcdir)/libfoo.map
+else
+libfoo_la_LDFLAGS += -export-symbols $(srcdir)/libfoo.sym
+endif
+...@end smallexample
+
+See the Libtool manual for the file syntax, but a small example would
+be:
+
+...@smallexample
+libfoo_init
+libfoo_doit
+libfoo_done
+...@end smallexample
+
+To avoid the need for a @code{*.sym} file if your symbols are easily
+expressed using a regular expression, you may use
+...@code{-export-symbols-regex}:
+
+...@smallexample
+if HAVE_LD_VERSION_SCRIPT
+libfoo_la_LDFLAGS += -Wl,--version-script=$(srcdir)/libfoo.map
+else
+libfoo_la_LDFLAGS += -export-symbols-regex '^libfoo_.*'
+endif
+...@end smallexample
+
+For more discussions about symbol visibility, rather than shared
+library versioning, see the @code{visibility} module
+(@pxref{visibility}).
diff --git a/doc/visibility.texi b/doc/visibility.texi
index c6dcbb8..2fbcbf5 100644
--- a/doc/visibility.texi
+++ b/doc/visibility.texi
@@ -1,3 +1,6 @@
+...@node visibility
+...@section visibility
+
@c Documentation of gnulib module 'visibility'.
@c Copyright (C) 2005-2006, 2009 Free Software Foundation, Inc.
diff --git a/m4/ld-version-script.m4 b/m4/ld-version-script.m4
new file mode 100644
index 0000000..e321347
--- /dev/null
+++ b/m4/ld-version-script.m4
@@ -0,0 +1,39 @@
+# ld-version-script.m4 serial 1
+dnl Copyright (C) 2008, 2009 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Simon Josefsson
+
+# gl_LD_VERSION_SCRIPT
+# --------------------
+# Check if LD supports linker scripts, and define automake conditional
+# HAVE_LD_VERSION_SCRIPT if so.
+AC_DEFUN([gl_LD_VERSION_SCRIPT],
+[
+ AC_ARG_ENABLE([ld-version-script],
+ AS_HELP_STRING([--enable-ld-version-script],
+ [enable linker version script (default is enabled when possible)]),
+ [have_ld_version_script=$enableval], [])
+ if test -z "$have_ld_version_script"; then
+ AC_MSG_CHECKING([if LD -Wl,--version-script works])
+ save_LDFLAGS="$LDFLAGS"
+ LDFLAGS="$LDFLAGS -Wl,--version-script=conftest.map"
+ cat > conftest.map <<EOF
+VERS_1 {
+ global: sym;
+};
+
+VERS_2 {
+ global: sym;
+} VERS_1;
+EOF
+ AC_LINK_IFELSE(AC_LANG_PROGRAM([], []),
+ [have_ld_version_script=yes], [have_ld_version_script=no])
+ rm -f conftest.map
+ LDFLAGS="$save_LDFLAGS"
+ AC_MSG_RESULT($have_ld_version_script)
+ fi
+ AM_CONDITIONAL(HAVE_LD_VERSION_SCRIPT, test "$have_ld_version_script" =
"yes")
+])
diff --git a/modules/ld-version-script b/modules/ld-version-script
new file mode 100644
index 0000000..6b0d990
--- /dev/null
+++ b/modules/ld-version-script
@@ -0,0 +1,14 @@
+Description:
+Macros to test whether LD support --linker-script.
+
+Files:
+m4/ld-version-script.m4
+
+configure.ac:
+gl_LD_VERSION_SCRIPT
+
+License:
+unlimited
+
+Maintainer:
+Simon Josefsson
--
1.5.6.5
