--- a/config.h.bot	Sun Dec 24 06:47:19 1995 +0000
+++ b/config.h.bot	Sun Dec 24 07:09:37 1995 +0000
@@ -4,3 +4,7 @@
 #else
 #define NORETURN
 #endif
+
+#if defined (WITH_DL) || defined (WITH_SHL) || defined (WITH_DLD)
+#define WITH_DYNAMIC_LINKING 1
+#endif

--- a/configure.in	Sun Dec 24 06:47:19 1995 +0000
+++ b/configure.in	Sun Dec 24 07:09:37 1995 +0000
@@ -20,7 +20,7 @@
 ### along with Octave; see the file COPYING.  If not, write to the Free
 ### Software Foundation, 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 
-AC_REVISION($Revision: 1.142 $)
+AC_REVISION($Revision: 1.143 $)
 AC_PREREQ(2.0)
 AC_INIT(src/octave.cc)
 AC_CONFIG_HEADER(config.h)
@@ -66,6 +66,23 @@
   use_dld=false)
 AC_SUBST(use_dld)
 
+### Allow the user to experiment with dynamic linking using dlopen/dlsym.
+
+AC_ARG_ENABLE(dl,
+  [  --enable-dl             use dlopen/dlsym for dynamic linking (not all systems)],
+  [if test $enableval = no; then use_dl=false; else use_dl=true; fi],
+  use_dl=false)
+AC_SUBST(use_dl)
+
+### Allow the user to experiment with dynamic linking using
+### shl_load/shl_findsym (HP/UX only?).
+
+AC_ARG_ENABLE(shl,
+  [  --enable-shl            use shl_load/shl_findsym for dynamic linking (HP only?)],
+  [if test $enableval = no; then use_shl=false; else use_shl=true; fi],
+  use_shl=false)
+AC_SUBST(use_shl)
+
 ### Allow compilation of smaller kernel.  This only works if some form
 ### of dynamic linking is also supported and used.
 
@@ -294,7 +311,7 @@
 changequote(,)dnl
   1.*|2.[012345].*)
 changequote([,])dnl
-    AC_MSG_WARN([g++ version $gxx_version will not work to compile Octave])
+    AC_MSG_ERROR([g++ version $gxx_version will not work to compile Octave])
   ;;
   *)
     AC_MSG_WARN([Octave has only been tested with g++, and I can't find it])
@@ -494,8 +511,7 @@
 else
   AC_MSG_WARN([in order to build octave, you must have a compatible])
   AC_MSG_WARN([Fortran compiler or f2c installed and in your path.])
-  AC_MSG_WARN([See the file INSTALL for more information.])
-  AC_MSG_WARN([Continuing anyway...])
+  AC_MSG_ERROR([See the file INSTALL for more information.])
 fi
 
 FC=$F77
@@ -585,6 +601,37 @@
 AC_CHECK_FUNCS(mkdir rmdir rename umask)
 AC_CHECK_FUNCS(sigaction sigprocmask sigpending sigsuspend)
 
+AC_CHECK_LIB(dl, dlopen)
+AC_CHECK_FUNCS(dlopen dlsym dlerror dlclose)
+
+if test "$ac_cv_func_dlopen" = yes \
+    && test "$ac_cv_func_dlopen" = yes \
+    && test "$ac_cv_func_dlsym" = yes \
+    && test "$ac_cv_func_dlerror" = yes \
+    && test "$ac_cv_func_dlclose" = yes; then
+  use_dl=true
+elif $use_dl; then
+  AC_MSG_ERROR([--enable-dl specified, but required functions are missing!])
+fi
+
+if $use_dl; then
+  AC_DEFINE(WITH_DL, 1)
+fi
+
+AC_CHECK_LIB(dld, shl_load)
+AC_CHECK_FUNCS(shl_load shl_findsym)
+
+if test "$ac_cv_func_shl_load" = yes \
+    && test "$ac_cv_func_shl_findsym" = yes; then
+  use_shl=true
+elif $use_shl; then
+  AC_MSG_ERROR([--enable-shl specified, but required functions are missing!])
+fi
+
+if $use_shl; then
+  AC_DEFINE(WITH_SHL, 1)
+fi
+
 ### There is more than one possible prototype for gettimeofday.  See
 ### which one (if any) appears in sys/time.h.
 
@@ -826,12 +873,8 @@
 
 ### Do the substitutions in all the Makefiles.
 
-define([tmpA], [Makefile octMakefile Makeconf])dnl
-define([tmpB], [liboctave/Makefile src/Makefile dld/Makefile])dnl
-define([tmpC], [doc/Makefile test/Makefile])dnl
-define([srcdirs], [tmpA tmpB tmpC])dnl
-
-AC_OUTPUT([srcdirs])
+AC_OUTPUT(Makefile octMakefile Makeconf liboctave/Makefile
+	  src/Makefile dld/Makefile doc/Makefile test/Makefile)
 
 ### Print a summary so that important information isn't missed.
 
@@ -847,16 +890,19 @@
 
 Octave is now configured for $canonical_host_type
 
-  Source directory:       $srcdir
-  Installation prefix:    $prefix
-  C compiler:             $CC $GCC_IEEE_FP_FLAG $CFLAGS
-  C++ compiler:           $CXX $CXX_EXTRAS $CXXFLAGS
-  Fortran compiler:       $FORT
-  Fortran libraries:      $FLIBS
-  Dynamic Linking:        $use_dld
-  Minimal kernel option:  $lite_kernel
-  Use GNU readline:       $USE_READLINE
-  Use GNU info reader:    $USE_GNU_INFO
-  Default pager:          $DEFAULT_PAGER
-  gnuplot:                $GNUPLOT_BINARY
+  Source directory:     $srcdir
+  Installation prefix:  $prefix
+  C compiler:           $CC $GCC_IEEE_FP_FLAG $CFLAGS
+  C++ compiler:         $CXX $CXX_EXTRAS $CXXFLAGS
+  Fortran compiler:     $FORT
+  Fortran libraries:    $FLIBS
+  Use GNU readline:     $USE_READLINE
+  Use GNU info reader:  $USE_GNU_INFO
+  Default pager:        $DEFAULT_PAGER
+  gnuplot:              $GNUPLOT_BINARY
+
+  Minimal kernel option:                   $lite_kernel
+  Dynamic Linking (dld):                   $use_dld
+  Dynamic Linking (dlopen/dlsym):          $use_dl
+  Dynamic Linking (shl_load/shl_findsym):  $use_shl
 ])

--- a/src/dynamic-ld.cc	Sun Dec 24 06:47:19 1995 +0000
+++ b/src/dynamic-ld.cc	Sun Dec 24 07:09:37 1995 +0000
@@ -25,11 +25,20 @@
 #include <config.h>
 #endif
 
+#if defined (WITH_SHL)
+#include <cerrno>
+#include <cstring>
+#endif
+
 #include <strstream.h>
 
 extern "C"
 {
-#ifdef WITH_DLD
+#if defined (WITH_DL)
+#include <dlfcn.h>
+#elif defined (WITH_SHL)
+#include <dl.h>
+#elif defined (WITH_DLD)
 #include <dld/dld.h>
 #endif
 }
@@ -47,11 +56,120 @@
 
 typedef builtin_function * (*Octave_builtin_fcn_struct_fcn)(void);
 
+#if defined (WITH_DYNAMIC_LINKING)
+
+// XXX FIXME XXX -- need to provide some way to ensure that functions
+// that we are going to use will use the same naming convention as
+// Octave's internal functions.  It needs to be simpler than the
+// current DEFUN_DLD() macro, which assumes you know how to name the
+// function, the struct, and the helper function.
+
+static char *
+mangle_octave_builtin_name (const char *name)
+{
+  char *tmp = strconcat (name, "__FRC13Octave_objecti");
+  char *retval = strconcat ("F", tmp);
+  delete [] tmp;
+  return retval;
+}
+
+static char *
+mangle_octave_oct_file_name (const char *name)
+{
+  char *tmp = strconcat (name, "__Fv");
+  char *retval = strconcat ("FS", tmp);
+  delete [] tmp;
+  return retval;
+}
+
+#endif
+
+#if defined (WITH_DL)
+
+static void *
+dl_resolve_octave_reference (const char *name, const char *file)
+{
+  // Dynamic linking with dlopen/dlsym doesn't require specification
+  // of the libraries at runtime.  Instead, they are specified when
+  // the .oct file is created.
+
+  void *handle = dlopen (file, RTLD_LAZY);
+
+  if (handle)
+    {
+      void *func = dlsym (handle, name);
+
+      if (func)
+	return func;
+      else
+	{
+	  const char *errmsg = dlerror ();
+
+	  if (errmsg)
+	    error("%s: `%s'", name, errmsg);
+	  else
+	    error("unable to link function `%s'", name);
+
+	  dlclose (handle);
+	  return 0;
+	}
+    }
+  else
+    {
+      error ("%s: %s `%s'", dlerror (), file, name);
+      return 0;
+    }
+}
+
+#elif defined (WITH_SHL)
+
+static void *
+shl_resolve_octave_reference (const char *name, const char *file)
+{
+  // Dynamic linking with shl_load/shl_findsym doesn't require
+  // specification of the libraries at runtime.  Instead, they are
+  // specified when the .oct file is created.
+
+  void *handle = shl_load (file, BIND_DEFERRED, 0L);
+
+  if (handle)
+    {
+      void *func = 0;
+
+      int status = shl_findsym ((shl_t *) &handle, name,
+				TYPE_UNDEFINED, func);
+
+      if (status < 0)
+	{
+	  const char *errmsg = strerror (errno);
+
+	  if (errmsg)
+	    error("%s: `%s'", name, errmsg);
+	  else
+	    error("unable to link function `%s'", name);
+
+	  return 0;
+	}
+      else
+	return func;
+    }
+  else
+    {
+      error ("%s: %s `%s'", strerror (errno), file, name);
+      return 0;
+    }
+}
+
+#elif defined (WITH_DLD)
+
+// Now that we have the code above to do dynamic linking with the
+// dlopen/dlsym interface and Linux uses elf, I doubt that this code
+// will be used very much.  Maybe it will be able to go away
+// eventually.  Consider it unsupported...
+
 // XXX FIXME XXX -- should this list be in a user-level variable,
 // with default taken from the environment?
 
-#ifdef WITH_DLD
-
 #ifndef STD_LIB_PATH
 #define STD_LIB_PATH "/lib:/usr/lib:/usr/local/lib"
 #endif
@@ -77,24 +195,6 @@
 
 static char *lib_list = OCTAVE_LIB_LIST ":" FLIB_LIST ":" SYSTEM_LIB_LIST;
 
-static char *
-mangle_octave_builtin_name (const char *name)
-{
-  char *tmp = strconcat (name, "__FRC13Octave_objecti");
-  char *retval = strconcat ("F", tmp);
-  delete [] tmp;
-  return retval;
-}
-
-static char *
-mangle_octave_oct_file_name (const char *name)
-{
-  char *tmp = strconcat (name, "__Fv");
-  char *retval = strconcat ("FS", tmp);
-  delete [] tmp;
-  return retval;
-}
-
 static void
 octave_dld_init (void)
 {
@@ -143,7 +243,7 @@
 }
 
 static void *
-dld_octave_resolve_reference (const char *name, const char *file = 0)
+dld_resolve_octave_reference (const char *name, const char *file)
 {
   dld_create_reference (name);
 
@@ -151,7 +251,7 @@
     {
       if (dld_link (file) != 0)
 	{
-	  error ("failed to link file %s", file);
+	  error ("failed to link file `%s'", file);
 	  return 0;
 	}
 
@@ -194,23 +294,51 @@
   return 0;
 }
 
-static Octave_builtin_fcn
-dld_octave_builtin (const char *name)
+#endif
+
+static void *
+resolve_octave_reference (const char *name, const char *file = 0)
+{
+#if defined (WITH_DL)
+
+  dl_resolve_octave_reference (name, file);
+
+#elif defined (WITH_SHL)
+
+  shl_resolve_octave_reference (name, file);
+
+#elif defined (WITH_DLD)
+
+  dld_resolve_octave_reference (name, file);
+
+#endif
+}
+
+Octave_builtin_fcn
+load_octave_builtin (const char *name)
 {
   Octave_builtin_fcn retval = 0;
 
+#if defined (WITH_DYNAMIC_LINKING)
+
   char *mangled_name = mangle_octave_builtin_name (name);
 
-  retval = (Octave_builtin_fcn) dld_octave_resolve_reference (mangled_name);
+  retval = (Octave_builtin_fcn) resolve_octave_reference (mangled_name);
 
   delete [] mangled_name;
 
+#endif
+
   return retval;
 }
 
-static int
-dld_octave_oct_file (const char *name)
+int
+load_octave_oct_file (const char *name)
 {
+  int retval = 0;
+
+#if defined (WITH_DYNAMIC_LINKING)
+
   char *oct_file = oct_file_in_path (name);
 
   if (oct_file)
@@ -218,7 +346,7 @@
       char *mangled_name = mangle_octave_oct_file_name (name);
 
       Octave_builtin_fcn_struct_fcn f =
-	(Octave_builtin_fcn_struct_fcn) dld_octave_resolve_reference
+	(Octave_builtin_fcn_struct_fcn) resolve_octave_reference
 	  (mangled_name, oct_file);
 
       if (f)
@@ -228,79 +356,32 @@
 	  if (s)
 	    {
 	      install_builtin_function (s);
-	      return 1;
+	      retval = 1;
 	    }
 	}
 
       delete [] oct_file;
     }
 
-  return 0;
-}
+#else
+
+  (void) name;
 
 #endif
 
-Octave_builtin_fcn
-load_octave_builtin (const char *name)
-{
-#ifdef WITH_DLD
-  return dld_octave_builtin (name);
-#else
-  (void) name;
-  return 0;
-#endif
-}
-
-int
-load_octave_oct_file (const char *name)
-{
-#ifdef WITH_DLD
-  return dld_octave_oct_file (name);
-#endif
-  (void) name;
-  return 0;
+  return retval;
 }
 
 void
 init_dynamic_linker (void)
 {
-#ifdef WITH_DLD
+#if defined (WITH_DLD)
+
   octave_dld_init ();
+
 #endif
 }
 
-// OLD:
-
-#if 0
-
-void
-octave_dld_tc2_unlink_by_symbol (const char *name, int hard)
-{
-  // XXX FIXME XXX -- need to determine the name mangling scheme
-  // automatically, in case it changes, or is different on different
-  // systems, even if they have g++.
-
-  char *mangled_fcn_name = strconcat (name, "__FRC13Octave_objecti");
-
-  int status = dld_unlink_by_symbol (mangled_fcn_name, hard);
-
-  if (status != 0)
-    error ("octave_dld_tc2_unlink_by_symbol: %s", dld_strerror (0));
-
-  delete [] mangled_fcn_name;
-}
-
-void
-octave_dld_tc2_unlink_by_file (const char *name, int hard)
-{
-  int status = dld_unlink_by_file (name, hard);
-
-  if (status != 0)
-    error ("octave_dld_tc2_unlink_by_file: %s", dld_strerror (0));
-}
-
-#endif
-
 /*
 ;;; Local Variables: ***
 ;;; mode: C++ ***

--- a/src/dynamic-ld.h	Sun Dec 24 06:47:19 1995 +0000
+++ b/src/dynamic-ld.h	Sun Dec 24 07:09:37 1995 +0000
@@ -34,13 +34,6 @@
 
 extern void init_dynamic_linker (void);
 
-// OLD:
-
-#if 0
-extern void octave_dld_tc2_unlink_by_symbol (const char *name, int hard = 1);
-extern void octave_dld_tc2_unlink_by_file (const char *name, int hard = 1);
-#endif
-
 #endif
 
 /*

--- a/src/utils.cc	Sun Dec 24 06:47:19 1995 +0000
+++ b/src/utils.cc	Sun Dec 24 07:09:37 1995 +0000
@@ -370,7 +370,7 @@
       while ((entry = readdir (dirp)) != 0)
 	{
 	  int len = NLENGTH (entry);
-#ifdef WITH_DLD
+#if defined (WITH_DYNAMIC_LINKING)
 	  if ((len > 2
 	       && entry->d_name[len-2] == '.'
 	       && entry->d_name[len-1] == 'm')