--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/dlopen.c	Mon Aug 13 10:17:54 2007 +0200
@@ -0,0 +1,138 @@
+/* Lisp interface to dynamic loading.
+   Copyright (C) 1998  Joshua Rowe.
+   Additional cleanup by Hrvoje Niksic.
+
+This file is part of XEmacs.
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; see the file COPYING.  If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA.  */
+
+/* Synched up with: Not in FSF. */
+
+/* A shared object may have the following symbols defined:
+      syms_of
+      vars_of
+      complex_vars_of
+   They are called in that order.  Each takes and returns void
+   arguments.
+
+   All of this needs lots and LOTS of work.  Some things to work on:
+
+   1) A good foreign interface.  We probably need to get rid of
+   syms_of and similar junk, and define a more normal interfacing to
+   the outside world, e.g. an init_emacs_module() function.  See below
+   for more discussion about it.  Also, we need a modules/ directory
+   with a few nice sample modules, a sample Makefile, etc. so people
+   can start hacking.
+
+   2) Compatibility concerns.  There are systems without dynamic
+   libraries (Ultrix, to name one).  OK, scrap them, but not all
+   systems out there use the exact dlopen() interface that this file
+   uses.  Bill Perry said he had ready Makefiles for 14 or so systems
+   to do this sort of things portably.  Check it out.  Or, use Gordon
+   Matzigkeit's libtool.
+
+   3) I'm getting coredumps very often -- practically every time I
+   compile without USE_MINIMAL_TAGBITS, and even with it sometimes.  I
+   wasn't able to resolve these.
+
+   4) All of this is sooo simple-minded.  As it gets more complex,
+   we'll have to look at how others have done similar things
+   (e.g. Perl and Zsh 3.1), to avoid botching it up.  */
+
+#include <config.h>
+#include "lisp.h"
+#include "emacsfns.h"
+#include "buffer.h"
+
+#include <stdio.h>
+#include <dlfcn.h>
+#include <errno.h>
+
+
+DEFUN ("dl-open", Fdl_open, 1, 1, "FShared object: ", /*
+Load LIBRARY as a shared object file.
+
+After the LIBRARY is dynamically linked with the executable, the
+following functions are called:
+
+  syms_of(),		containing definitions of symbols and subr's;
+  vars_of(),		containing definitions of variables;
+  complex_vars_of(),	containing complex definitions of variables.
+
+After this point, any lisp symbols defined in the shared object are
+available for use.
+*/
+       (library))
+{
+  /* This function can GC */
+  void *handle;
+  char *file;
+  void (*function)();
+
+  CHECK_STRING (library);
+  library = Fexpand_file_name (library, Qnil);
+
+  file = XSTRING_DATA (library);
+  /* #### Is this right? */
+  GET_C_CHARPTR_EXT_FILENAME_DATA_ALLOCA (file, file);
+
+  handle = dlopen (file, RTLD_LAZY);
+  if (handle == NULL)
+    {
+      signal_error (Qerror,
+		    list3 (build_translated_string ("Cannot load shared library"),
+			   library, build_translated_string (dlerror ())));
+    }
+
+  /* #### This looks unnecessary here, because at this time one
+     initialization function is fully sufficient.  However, I am not
+     removing this support, since we may wish to add mechanisms for
+     static linking, which would have invoke these function via normal
+     paths.
+
+     #### But then this is not sufficient, because one could as well
+     honor specifier_vars_of_foo(), etc.  Maybe we should scrap it
+     after all.
+
+     #### What if one of the first two functions signal an error?
+     Should we take care to execute the other two?  My fingers are
+     getting itchy!  */
+
+  function = dlsym (handle, "syms_of");
+  if (function)
+    {
+      function ();
+    }
+
+  function = dlsym (handle, "vars_of");
+  if (function)
+    {
+      function ();
+    }
+
+  function = dlsym (handle, "complex_vars_of");
+  if (function)
+    {
+      function ();
+    }
+
+  return Qnil;
+}
+
+void syms_of_dlopen ()
+{
+  DEFSUBR (Fdl_open);
+}