diff --git a/C/iopreds.c b/C/iopreds.c
index 9435c4852..40bb68b17 100644
--- a/C/iopreds.c
+++ b/C/iopreds.c
@@ -1658,6 +1658,22 @@ p_open (void)
 }
 
 
+static Int
+p_file_expansion (void)
+{				/* '$file_expansion'(+File,-Name)      */
+  Term file_name = Deref(ARG1);
+
+  /* we know file_name is bound */
+  if (!IsAtomTerm (file_name)) {
+    PlIOError(TYPE_ERROR_ATOM, file_name, "absolute_file_name/3");
+    return(FALSE);
+  }
+  if (!TrueFileName (RepAtom (AtomOfTerm (file_name))->StrOfAE, FileNameBuf, FALSE))
+    return (PlIOError (EXISTENCE_ERROR_SOURCE_SINK,file_name,"absolute_file_name/3"));
+  return(unify(ARG2,MkAtomTerm(LookupAtom(FileNameBuf))));
+}
+
+
 static Int p_add_alias_to_stream (void)
 {
   Term tname = Deref(ARG1);
@@ -4782,6 +4798,7 @@ InitIOPreds(void)
   InitCPred ("$get0_line_codes", 2, p_get0_line_codes, SafePredFlag|SyncPredFlag);
   InitCPred ("$get_byte", 2, p_get_byte, SafePredFlag|SyncPredFlag);
   InitCPred ("$open", 4, p_open, SafePredFlag|SyncPredFlag);
+  InitCPred ("$file_expansion", 2, p_file_expansion, SafePredFlag|SyncPredFlag);
   InitCPred ("$open_null_stream", 1, p_open_null_stream, SafePredFlag|SyncPredFlag);
   InitCPred ("$open_pipe_stream", 2, p_open_pipe_stream, SafePredFlag|SyncPredFlag);
   InitCPred ("open_mem_read_stream", 2, p_open_mem_read_stream, SyncPredFlag);
diff --git a/C/sysbits.c b/C/sysbits.c
index 6b4d0b529..aa7df4f47 100644
--- a/C/sysbits.c
+++ b/C/sysbits.c
@@ -1611,7 +1611,7 @@ p_shell (void)
 #else
 #if HAVE_SYSTEM 
   char *shell;
-  char *command = AllocTmpSpaceFromGlobal();
+#define command ((char *)TR)
   register int bourne = FALSE;
   Term t1 = Deref (ARG1);
 
@@ -1651,6 +1651,7 @@ p_shell (void)
 	return (result);
       }
     }
+#undef command
 #else /* HAVE_SYSTEM */
 #ifdef MSH
   register char *shell;
@@ -1670,7 +1671,7 @@ static Int
 p_system (void)
 {				/* '$system'(+SystCommand)	       */
 #ifdef HAVE_SYSTEM
-  char *command = AllocTmpSpaceFromGlobal();
+#define command ((char *)TR)
   Term t1 = Deref (ARG1);
   if (!GetName (command, t1)) {
     Error(SYSTEM_ERROR,t1,"argument to system/1 is not valid");
@@ -1688,6 +1689,7 @@ p_system (void)
   /* CloseStreams(); */
   system (shell);
   return (TRUE);
+#undef command
 #else
   Error(SYSTEM_ERROR,TermNil,"sh not available in this machine");
   return(FALSE);
diff --git a/H/Regs.h b/H/Regs.h
index a29c4af47..5a4e5cef2 100644
--- a/H/Regs.h
+++ b/H/Regs.h
@@ -10,7 +10,7 @@
 * File:		Regs.h							 *
 * mods:									 *
 * comments:	YAP abstract machine registers				 *
-* version:      $Id: Regs.h,v 1.8 2001-12-07 20:27:03 vsc Exp $	 *
+* version:      $Id: Regs.h,v 1.9 2002-01-02 05:35:20 vsc Exp $	 *
 *************************************************************************/
 
 
@@ -678,9 +678,6 @@ EXTERN inline void restore_B(void) {
 #define BBREG         BB
 #endif
 
-/* use global stack for intermediate data-structures */
-#define AllocTmpSpaceFromGlobal()           ((char *)H)
-
 #if !THREADS
 /* use actual addresses for regs */
 #define PRECOMPUTE_REGADDRESS 1
diff --git a/docs/yap.tex b/docs/yap.tex
index 50e051ffe..6d6308c78 100644
--- a/docs/yap.tex
+++ b/docs/yap.tex
@@ -3329,6 +3329,14 @@ Closes the stream @var{S}, following options @var{O}.
 The only valid options are @code{force(true)} and @code{force(false)}.
 YAP currently ignores these options.
 
+@item absolute_file_name(+@var{Name},-@var{FullPath})
+@findex absolute_file_name/2
+@syindex absolute_file_name/2
+@cnindex absolute_file_name/2
+Give the path a full path @var{FullPath} Yap would use to consule a file
+named @var{Name}.  Unify @var{FullPath} with @code{user} if the file
+name is @code{user}.
+
 @item current_stream(@var{F},@var{M},@var{S})
 @findex current_stream/3
 @syindex current_stream/3
diff --git a/pl/yio.yap b/pl/yio.yap
index 125e7c109..1abb8bc60 100644
--- a/pl/yio.yap
+++ b/pl/yio.yap
@@ -871,10 +871,14 @@ at_end_of_stream(S) :-
 
 consult_depth(LV) :- '$show_consult_level'(LV).
 
+absolute_file_name(V,Out) :-
+	throw(error(instantiation_error, absolute_file_name(V, Out))).
+absolute_file_name(user,user) :- !.
 absolute_file_name(RelFile,AbsFile) :-
 	'$find_in_path'(RelFile,PathFile),
-	'$exists'(PathFile,'$csult', AbsFile).
-
+	'$exists'(PathFile,'$csult', AbsFile), !.
+absolute_file_name(RelFile, AbsFile) :-
+	'$file_expansion'(RelFile, AbsFile).
 
 '$exists'(F,Mode,AbsFile) :-
 	'$get_value'(fileerrors,V),