diff --git a/C/c_interface.c b/C/c_interface.c
index c2a16b521..0986f82a4 100644
--- a/C/c_interface.c
+++ b/C/c_interface.c
@@ -425,6 +425,7 @@ X_API PredEntry *STD_PROTO(YAP_FunctorToPred,(Functor));
 X_API PredEntry *STD_PROTO(YAP_AtomToPred,(Atom));
 X_API Int     STD_PROTO(YAP_CallProlog,(Term));
 X_API void   *STD_PROTO(YAP_AllocSpaceFromYap,(unsigned int));
+X_API void   *STD_PROTO(YAP_ReallocSpaceFromYap,(void*,unsigned int));
 X_API void    STD_PROTO(YAP_FreeSpaceFromYap,(void *));
 X_API int     STD_PROTO(YAP_StringToBuffer, (Term, char *, unsigned int));
 X_API Term    STD_PROTO(YAP_ReadBuffer, (char *,Term *));
@@ -1292,6 +1293,19 @@ YAP_CallProlog(Term t)
   return(out);
 }
 
+X_API void *
+YAP_ReallocSpaceFromYap(void *ptr,unsigned int size) {
+  void *new_ptr;
+  BACKUP_MACHINE_REGS();
+  while ((new_ptr = Yap_ExpandPreAllocCodeSpace(size,ptr,TRUE)) == NULL) {
+    if (!Yap_growheap(FALSE, size, NULL)) {
+      Yap_Error(OUT_OF_HEAP_ERROR, TermNil, Yap_ErrorMessage);
+      return NULL;
+    }
+  }
+  RECOVER_MACHINE_REGS();
+  return new_ptr;
+}
 X_API void *
 YAP_AllocSpaceFromYap(unsigned int size)
 {
diff --git a/include/SWI-Prolog.h b/include/SWI-Prolog.h
index 5fc418526..dd418c4e2 100755
--- a/include/SWI-Prolog.h
+++ b/include/SWI-Prolog.h
@@ -280,6 +280,47 @@ typedef struct foreign_context *control_t;
 
 /* end from pl-itf.h */
 
+/* Required by PL_error */
+#define ERR_NO_ERROR		0
+#define ERR_INSTANTIATION	1	/* void */
+#define ERR_TYPE		2	/* atom_t expected, term_t value */
+#define ERR_DOMAIN		3	/* atom_t domain, term_t value */
+#define ERR_REPRESENTATION	4	/* atom_t what */
+#define ERR_MODIFY_STATIC_PROC	5	/* predicate_t proc */
+#define ERR_EVALUATION		6	/* atom_t what */
+#define ERR_AR_TYPE		7	/* atom_t expected, Number value */
+#define ERR_NOT_EVALUABLE	8	/* functor_t func */
+#define ERR_DIV_BY_ZERO		9	/* void */
+#define ERR_FAILED	       10	/* predicate_t proc */
+#define ERR_FILE_OPERATION     11	/* atom_t action, atom_t type, term_t */
+#define ERR_PERMISSION	       12	/* atom_t type, atom_t op, term_t obj*/
+#define ERR_NOT_IMPLEMENTED 13	/* const char *what */
+#define ERR_EXISTENCE	       14	/* atom_t type, term_t obj */
+#define ERR_STREAM_OP	       15	/* atom_t action, term_t obj */
+#define ERR_RESOURCE	       16	/* atom_t resource */
+#define ERR_NOMEM	       17	/* void */
+#define ERR_SYSCALL	       18	/* void */
+#define ERR_SHELL_FAILED       19	/* term_t command */
+#define ERR_SHELL_SIGNALLED    20	/* term_t command, int signal */
+#define ERR_AR_UNDEF	       21	/* void */
+#define ERR_AR_OVERFLOW	       22	/* void */
+#define ERR_AR_UNDERFLOW       23	/* void */
+#define ERR_UNDEFINED_PROC     24	/* Definition def */
+#define ERR_SIGNALLED	       25	/* int sig, char *name */
+#define ERR_CLOSED_STREAM      26	/* IOSTREAM * */
+#define ERR_BUSY	       27	/* mutexes */
+#define ERR_PERMISSION_PROC    28	/* op, type, Definition */
+#define ERR_DDE_OP	       29	/* op, error */
+#define ERR_SYNTAX	       30	/* what */
+#define ERR_SHARED_OBJECT_OP   31	/* op, error */
+#define ERR_TIMEOUT	       32	/* op, object */
+#define ERR_NOT_IMPLEMENTED_PROC 33	/* name, arity */
+#define ERR_FORMAT	       34	/* message */
+#define ERR_FORMAT_ARG	       35	/* seq, term */
+#define ERR_OCCURS_CHECK       36	/* Word, Word */
+#define ERR_CHARS_TYPE	       37	/* char *, term */
+#define ERR_MUST_BE_VAR	       38	/* int argn, term_t term */
+
 		 /*******************************
 		 *	     CALL-BACK		*
 		 *******************************/
@@ -431,6 +472,7 @@ extern X_API void PL_recorded(record_t, term_t);
 extern X_API void PL_erase(record_t);
 extern X_API int PL_action(int,...);
 extern X_API void *PL_malloc(int);
+extern X_API void *PL_realloc(void*,int);
 extern X_API void PL_free(void *);
 extern X_API int  PL_eval_expression_to_int64_ex(term_t t, int64_t *val);
 
@@ -475,6 +517,7 @@ extern X_API  const char *PL_cwd(void);
 void swi_install(void);
 
 X_API int PL_error(const char *pred, int arity, const char *msg, int id, ...);
+X_API int PL_warning(const char *msg, ...);
 
 
 #ifdef __cplusplus
diff --git a/include/YapInterface.h b/include/YapInterface.h
index 9a0f3f15f..fe6819d6e 100644
--- a/include/YapInterface.h
+++ b/include/YapInterface.h
@@ -236,6 +236,9 @@ extern X_API void PROTO(YAP_cut_up,(void));
 /*  void *AllocSpaceFromYAP_(int) */
 extern X_API void *PROTO(YAP_AllocSpaceFromYap,(unsigned int));
 
+/*  void *ReallocSpaceFromYAP_(void*,int) */
+extern X_API void *PROTO(YAP_ReallocSpaceFromYap,(void*,unsigned int));
+
 /*  void FreeSpaceFromYAP_(void *) */
 extern X_API void PROTO(YAP_FreeSpaceFromYap,(void *));
 
diff --git a/library/yap2swi/yap2swi.c b/library/yap2swi/yap2swi.c
index a3c1df428..b8917bfae 100644
--- a/library/yap2swi/yap2swi.c
+++ b/library/yap2swi/yap2swi.c
@@ -900,45 +900,6 @@ X_API int PL_raise_exception(term_t exception)
 #define FUNCTOR_timeout_error2 FunctorToSWIFunctor(FunctorTimeoutError)
 #define FUNCTOR_type_error2 FunctorToSWIFunctor(FunctorTypeError)
 
-#define ERR_NO_ERROR		0
-#define ERR_INSTANTIATION	1	/* void */
-#define ERR_TYPE		2	/* atom_t expected, term_t value */
-#define ERR_DOMAIN		3	/* atom_t domain, term_t value */
-#define ERR_REPRESENTATION	4	/* atom_t what */
-#define ERR_MODIFY_STATIC_PROC	5	/* predicate_t proc */
-#define ERR_EVALUATION		6	/* atom_t what */
-#define ERR_AR_TYPE		7	/* atom_t expected, Number value */
-#define ERR_NOT_EVALUABLE	8	/* functor_t func */
-#define ERR_DIV_BY_ZERO		9	/* void */
-#define ERR_FAILED	       10	/* predicate_t proc */
-#define ERR_FILE_OPERATION     11	/* atom_t action, atom_t type, term_t */
-#define ERR_PERMISSION	       12	/* atom_t type, atom_t op, term_t obj*/
-#define ERR_NOT_IMPLEMENTED 13	/* const char *what */
-#define ERR_EXISTENCE	       14	/* atom_t type, term_t obj */
-#define ERR_STREAM_OP	       15	/* atom_t action, term_t obj */
-#define ERR_RESOURCE	       16	/* atom_t resource */
-#define ERR_NOMEM	       17	/* void */
-#define ERR_SYSCALL	       18	/* void */
-#define ERR_SHELL_FAILED       19	/* term_t command */
-#define ERR_SHELL_SIGNALLED    20	/* term_t command, int signal */
-#define ERR_AR_UNDEF	       21	/* void */
-#define ERR_AR_OVERFLOW	       22	/* void */
-#define ERR_AR_UNDERFLOW       23	/* void */
-#define ERR_UNDEFINED_PROC     24	/* Definition def */
-#define ERR_SIGNALLED	       25	/* int sig, char *name */
-#define ERR_CLOSED_STREAM      26	/* IOSTREAM * */
-#define ERR_BUSY	       27	/* mutexes */
-#define ERR_PERMISSION_PROC    28	/* op, type, Definition */
-#define ERR_DDE_OP	       29	/* op, error */
-#define ERR_SYNTAX	       30	/* what */
-#define ERR_SHARED_OBJECT_OP   31	/* op, error */
-#define ERR_TIMEOUT	       32	/* op, object */
-#define ERR_NOT_IMPLEMENTED_PROC 33	/* name, arity */
-#define ERR_FORMAT	       34	/* message */
-#define ERR_FORMAT_ARG	       35	/* seq, term */
-#define ERR_OCCURS_CHECK       36	/* Word, Word */
-#define ERR_CHARS_TYPE	       37	/* char *, term */
-#define ERR_MUST_BE_VAR	       38	/* int argn, term_t term */
 
 static char *
 OsError(void)
@@ -968,6 +929,17 @@ static char errmsg[64];
 #endif /*HAVE_STRERROR*/
 }
 
+X_API int PL_warning(const char *msg, ...) {
+  va_list args;
+  va_start(args, msg);
+  // just print the warning message and return? 
+  fprintf(stderr,"[Warning:");
+  fprintf(stderr,msg,args);
+  fprintf(stderr,"]\n");
+  va_end(args);
+  PL_fail;
+}
+
 X_API int PL_error(const char *pred, int arity, const char *msg, int id, ...)
 {
   term_t formal, swi, predterm, msgterm, except;
@@ -1142,6 +1114,7 @@ X_API int PL_error(const char *pred, int arity, const char *msg, int id, ...)
 		      PL_ATOM, what);
       break;
     }
+      
   default:
     fprintf(stderr, "unimplemented SWI error %d\n",id);
     goto err_instantiation;
@@ -2193,6 +2166,12 @@ PL_malloc(int sz)
   return YAP_AllocSpaceFromYap(sz);
 }
 
+X_API void *
+PL_realloc(void *ptr, int sz)
+{
+  return YAP_ReallocSpaceFromYap(ptr,sz);
+}
+
 X_API void
 PL_free(void *obj)
 {