diff -pru pari-2.9.0-ini/src/language/anal.c pari-2.9.0/src/language/anal.c
--- pari-2.9.0-ini/src/language/anal.c	2016-10-07 07:16:44.000000000 -0700
+++ pari-2.9.0/src/language/anal.c	2019-03-06 02:55:52.192006500 -0800
@@ -261,6 +261,10 @@ findentry(const char *s, long len, entre
       if (!strncmp(t, s, len) && !t[len]) return ep;
     }
   /* not found */
+  if (foreignAutoload) {	/* Try to autoload. */
+    ep = foreignAutoload(s,len);
+    if(ep) return ep;
+  }  /* not found */
   if (insert) { ep = initep(s,len); insertep(ep, T, hash); }
   return ep;
 }
@@ -317,7 +317,7 @@ check_proto(const char *code)
 {
   long arity = 0;
   const char *s = code, *old;
-  if (*s == 'l' || *s == 'v' || *s == 'i' || *s == 'm' || *s == 'u') s++;
+  if (*s == 'l' || *s == 'v' || *s == 'i' || *s == 'm' || *s == 'u' || *s == 'x') arity += (*s == 'x'), s++;
   while (*s && *s != '\n') switch (*s++)
   {
     case '&':
@@ -353,6 +357,7 @@ check_proto(const char *code)
     case ',': break;
     case '\n': break; /* Before the mnemonic */
 
+    case 'x':
     case 'm':
     case 'l':
     case 'i':
@@ -383,7 +388,11 @@ install(void *f, const char *name, const
   {
     if (ep->valence != EpINSTALL)
       pari_err(e_MISC,"[install] identifier '%s' already in use", name);
-    pari_warn(warner, "[install] updating '%s' prototype; module not reloaded", name);
+    if (foreignFuncFree && ep->code && (*ep->code == 'x'))
+      (*foreignFuncFree)(ep); /* function created by foreign interpreter */
+    else
+      pari_warn(warner, "[install] updating '%s' prototype; module not reloaded", name);
+
     if (ep->code) pari_free((void*)ep->code);
   }
   else
diff -pru pari-2.9.0-ini/src/language/anal.h pari-2.9.0/src/language/anal.h
--- pari-2.9.0-ini/src/language/anal.h	2016-10-01 04:23:18.000000000 -0700
+++ pari-2.9.0/src/language/anal.h	2019-03-06 02:48:18.136608900 -0800
@@ -34,6 +34,9 @@ void   pari_fill_hashtable(entree **tabl
 void compile_err(const char *msg, const char *str);
 void compile_varerr(const char *str);
 
+extern entree * (*foreignAutoload)(const char*, long len);
+extern void (*foreignFuncFree)(entree *);
+
 #ifdef STACK_CHECK
 extern THREAD void *PARI_stack_limit;
 #endif
diff -pru pari-2.9.0-ini/src/language/compile.c pari-2.9.0/src/language/compile.c
--- pari-2.9.0-ini/src/language/compile.c	2016-10-05 02:43:38.000000000 -0700
+++ pari-2.9.0/src/language/compile.c	2019-03-06 02:48:18.027408700 -0800
@@ -519,9 +519,10 @@ detag(long n)
 
 /* return type for GP functions */
 static op_code
-get_ret_type(const char **p, long arity, Gtype *t, long *flag)
+get_ret_type(const char **p, long arity, Gtype *t, long *flag, long *is_external)
 {
-  *flag = 0;
+  *flag = *is_external = 0;
+  if (**p == 'x') { (*p)++; *is_external = 1; }
   if (**p == 'v') { (*p)++; *t=Gvoid; return OCcallvoid; }
   else if (**p == 'i') { (*p)++; *t=Gsmall;  return OCcallint; }
   else if (**p == 'l') { (*p)++; *t=Gsmall;  return OCcalllong; }
@@ -1203,7 +1204,7 @@ compilefunc(entree *ep, long n, int mode
   long j;
   long x=tree[n].x, y=tree[n].y;
   op_code ret_op;
-  long ret_flag;
+  long ret_flag, is_external;
   Gtype ret_typ;
   char const *p,*q;
   char c;
@@ -1335,8 +1335,9 @@ compilefunc(entree *ep, long n, int mode
   if (!ep->value)
     compile_err("unknown function",tree[n].str);
   nbopcodes = s_opcode.n;
-  ret_op = get_ret_type(&p, ep->arity, &ret_typ, &ret_flag);
+  ret_op = get_ret_type(&p, ep->arity, &ret_typ, &ret_flag, &is_external);
   j=1;
+  if (is_external) op_push(OCpushlong,(long)ep,n);	/* as in PPauto */
   if (*p)
   {
     q=p;
@@ -1661,8 +1663,8 @@ genclosure(entree *ep, const char *loc,
   long arity=0, maskarg=0, maskarg0=0, stop=0, dovararg=0;
   PPproto mod;
   Gtype ret_typ;
-  long ret_flag;
-  op_code ret_op=get_ret_type(&code,ep->arity,&ret_typ,&ret_flag);
+  long ret_flag, is_external;
+  op_code ret_op=get_ret_type(&code,ep->arity,&ret_typ,&ret_flag,&is_external);
   p=code;
   while ((mod=parseproto(&p,&c,NULL))!=PPend)
   {
@@ -1705,6 +1707,7 @@ genclosure(entree *ep, const char *loc,
   if (maskarg)  op_push_loc(OCcheckargs,maskarg,loc);
   if (maskarg0) op_push_loc(OCcheckargs0,maskarg0,loc);
   p=code;
+  if (is_external) op_push_loc(OCpushlong,(long)ep,loc);	/* as in PPauto */
   while ((mod=parseproto(&p,&c,NULL))!=PPend)
   {
     switch(mod)
@@ -2292,14 +2292,14 @@ optimizefunc(entree *ep, long n)
   const char *p;
   char c;
   GEN arg = listtogen(y,Flistarg);
-  long nb=lg(arg)-1, ret_flag;
+  long nb=lg(arg)-1, ret_flag, is_external /* ignored */;
   if (is_func_named(ep,"if") && nb>=4)
     ep=is_entry("_multi_if");
   p = ep->code;
   if (!p)
     fl=0;
   else
-    (void) get_ret_type(&p, 2, &t, &ret_flag);
+    (void) get_ret_type(&p, 2, &t, &ret_flag, &is_external);
   if (p && *p)
   {
     j=1;
diff -pru pari-2.9.0-ini/src/language/eval.c pari-2.9.0/src/language/eval.c
--- pari-2.9.0-ini/src/language/eval.c	2016-10-05 02:43:38.000000000 -0700
+++ pari-2.9.0/src/language/eval.c	2019-03-06 02:58:32.731888400 -0800
@@ -138,6 +138,9 @@ pop_val(entree *ep)
 void
 freeep(entree *ep)
 {
+  if (foreignFuncFree && ep->code && (*ep->code == 'x'))
+    (*foreignFuncFree)(ep); /* function created by foreign interpreter */
+
   if (EpSTATIC(ep)) return; /* gp function loaded at init time */
   if (ep->help) {pari_free((void*)ep->help); ep->help=NULL;}
   if (ep->code) {pari_free((void*)ep->code); ep->code=NULL;}
@@ -1535,7 +1538,8 @@ evalstate_reset(void)
   reset_break();
   compilestate_reset();
   parsestate_reset();
-  avma = pari_mainstack->top;
+  if (!cb_exception_resets_avma)
+    avma = pari_mainstack->top;
 }
 
 void
diff -pru pari-2.9.0-ini/src/language/init.c pari-2.9.0/src/language/init.c
--- pari-2.9.0-ini/src/language/init.c	2016-10-25 01:15:32.000000000 -0700
+++ pari-2.9.0/src/language/init.c	2019-03-06 03:00:07.190054300 -0800
@@ -113,6 +113,9 @@ static pari_stack s_MODULES;
 const long functions_tblsz = 135; /* size of functions_hash */
 entree **functions_hash, **defaults_hash;
 
+entree* (*foreignAutoload)(const char*, long len); /* Autoloader         */
+void (*foreignFuncFree)(entree *);    /* How to free external entree.    */
+
 char *(*cb_pari_fgets_interactive)(char *s, int n, FILE *f);
 int (*cb_pari_get_line_interactive)(const char*, const char*, filtre_t *F);
 void (*cb_pari_quit)(long);
@@ -130,6 +133,9 @@ void (*cb_pari_start_output)();
 
 const char * pari_library_path = NULL;
 
+int cb_exception_resets_avma = 0;
+int cb_exception_flushes_err = 0;
+
 static THREAD GEN global_err_data;
 THREAD jmp_buf *iferr_env;
 const long CATCH_ALL = -1;
@@ -1141,7 +1147,8 @@ pari_sigint(const char *time_s)
   out_puts(pariErr, "user interrupt after ");
   out_puts(pariErr, time_s);
   out_term_color(pariErr, c_NONE);
-  pariErr->flush();
+  if (!cb_exception_flushes_err)
+    pariErr->flush();
   if (cb_pari_handle_exception)
     recover = cb_pari_handle_exception(-1);
   if (!recover && !block)
@@ -1505,7 +1505,9 @@ pari_err_display(GEN err)
     pari_free(s);
   }
   out_term_color(pariErr, c_NONE);
-  pariErr->flush(); return 0;
+  if (!cb_exception_flushes_err)
+    pariErr->flush();
+  return 0;
 }
 
 void
--- pari-2.9.0/src/headers/paricom.h-pre	2011-05-30 02:28:34.000000000 -0700
+++ pari-2.9.0/src/headers/paricom.h	2018-09-16 00:04:16.527215600 -0700
@@ -92,6 +92,10 @@ extern void (*cb_pari_start_output)(void
 extern const char *pari_library_path;
 extern THREAD long *varpriority;
 
+#define CB_EXCEPTION_FLAGS 1
+extern int cb_exception_resets_avma;
+extern int cb_exception_flushes_err;
+
 /* pari_init_opts */
 enum {
   INIT_JMPm = 1,