diff -r c0426a6b39a0 sipgen/metasrc/lexer.l
--- a/sipgen/metasrc/lexer.l	Fri Feb 26 15:26:24 2021 +0000
+++ b/sipgen/metasrc/lexer.l	Mon Dec 06 12:26:46 2021 +0100
@@ -179,6 +179,7 @@
 <directive>call_super_init  {return TK_CALLSUPERINIT;}
 <directive>default_VirtualErrorHandler  {return TK_DEFERRORHANDLER;}
 <directive>version          {return TK_VERSION;}
+<directive>py_ssize_t_clean {return;}
 
 <directive>True             {return TK_TRUE_VALUE;}
 <directive>False            {return TK_FALSE_VALUE;}
diff -r c0426a6b39a0 sipgen/metasrc/parser.y
--- a/sipgen/metasrc/parser.y	Fri Feb 26 15:26:24 2021 +0000
+++ b/sipgen/metasrc/parser.y	Mon Dec 06 12:26:46 2021 +0100
@@ -1908,7 +1908,7 @@
             if (notSkipping())
                 currentModule = configureModule(currentSpec, currentModule,
                         currentContext.filename, $2.name, $2.c_module,
-                        $2.kwargs, $2.use_arg_names, $2.use_limited_api,
+                        $2.kwargs, $2.use_arg_names, $2.use_limited_api, $2.py_ssize_t_clean,
                         $2.call_super_init, $2.all_raise_py_exc,
                         $2.def_error_handler, $3.docstring);
         }
@@ -1930,6 +1930,7 @@
             $$.kwargs = defaultKwArgs;
             $$.name = $1;
             $$.use_arg_names = FALSE;
+            $$.py_ssize_t_clean = FALSE;
             $$.use_limited_api = FALSE;
             $$.all_raise_py_exc = FALSE;
             $$.call_super_init = -1;
@@ -1950,6 +1951,7 @@
             case TK_LANGUAGE: $$.c_module = $3.c_module; break;
             case TK_NAME: $$.name = $3.name; break;
             case TK_USEARGNAMES: $$.use_arg_names = $3.use_arg_names; break;
+            case TK_PYSSIZETCLEAN: $$.py_ssize_t_clean = $3.py_ssize_t_clean; break;
             case TK_USELIMITEDAPI: $$.use_limited_api = $3.use_limited_api; break;
             case TK_ALLRAISEPYEXC: $$.all_raise_py_exc = $3.all_raise_py_exc; break;
             case TK_CALLSUPERINIT: $$.call_super_init = $3.call_super_init; break;
@@ -1965,7 +1967,9 @@
             $$.kwargs = convertKwArgs($3);
             $$.name = NULL;
             $$.use_arg_names = FALSE;
+            $$.py_ssize_t_clean = FALSE;
             $$.use_limited_api = FALSE;
+            $$.py_ssize_t_clean = FALSE;
             $$.all_raise_py_exc = FALSE;
             $$.call_super_init = -1;
             $$.def_error_handler = NULL;
@@ -1983,6 +1987,7 @@
             $$.kwargs = defaultKwArgs;
             $$.name = NULL;
             $$.use_arg_names = FALSE;
+            $$.py_ssize_t_clean = FALSE;
             $$.use_limited_api = FALSE;
             $$.all_raise_py_exc = FALSE;
             $$.call_super_init = -1;
@@ -1995,6 +2000,7 @@
             $$.kwargs = defaultKwArgs;
             $$.name = $3;
             $$.use_arg_names = FALSE;
+            $$.py_ssize_t_clean = FALSE;
             $$.use_limited_api = FALSE;
             $$.all_raise_py_exc = FALSE;
             $$.call_super_init = -1;
@@ -2007,6 +2013,7 @@
             $$.kwargs = defaultKwArgs;
             $$.name = NULL;
             $$.use_arg_names = $3;
+            $$.py_ssize_t_clean = FALSE;
             $$.use_limited_api = FALSE;
             $$.all_raise_py_exc = FALSE;
             $$.call_super_init = -1;
@@ -2019,6 +2026,7 @@
             $$.kwargs = defaultKwArgs;
             $$.name = NULL;
             $$.use_arg_names = FALSE;
+            $$.py_ssize_t_clean = FALSE;
             $$.use_limited_api = $3;
             $$.all_raise_py_exc = FALSE;
             $$.call_super_init = -1;
@@ -2031,6 +2039,7 @@
             $$.kwargs = defaultKwArgs;
             $$.name = NULL;
             $$.use_arg_names = FALSE;
+            $$.py_ssize_t_clean = FALSE;
             $$.use_limited_api = FALSE;
             $$.all_raise_py_exc = $3;
             $$.call_super_init = -1;
@@ -2043,6 +2052,7 @@
             $$.kwargs = defaultKwArgs;
             $$.name = NULL;
             $$.use_arg_names = FALSE;
+            $$.py_ssize_t_clean = FALSE;
             $$.use_limited_api = FALSE;
             $$.all_raise_py_exc = FALSE;
             $$.call_super_init = $3;
@@ -2055,6 +2065,7 @@
             $$.kwargs = defaultKwArgs;
             $$.name = NULL;
             $$.use_arg_names = FALSE;
+            $$.py_ssize_t_clean = FALSE;
             $$.use_limited_api = FALSE;
             $$.all_raise_py_exc = FALSE;
             $$.call_super_init = -1;
@@ -2072,6 +2083,7 @@
             $$.kwargs = defaultKwArgs;
             $$.name = NULL;
             $$.use_arg_names = FALSE;
+            $$.py_ssize_t_clean = FALSE;
             $$.use_limited_api = FALSE;
             $$.all_raise_py_exc = FALSE;
             $$.call_super_init = -1;
@@ -9513,7 +9525,7 @@
  */
 static moduleDef *configureModule(sipSpec *pt, moduleDef *module,
         const char *filename, const char *name, int c_module, KwArgs kwargs,
-        int use_arg_names, int use_limited_api, int call_super_init,
+        int use_arg_names, int py_ssize_t_clean, int use_limited_api, int call_super_init,
         int all_raise_py_exc, const char *def_error_handler,
         docstringDef *docstring)
 {
diff -r c0426a6b39a0 sipgen/sip.h.in
--- a/sipgen/sip.h	Fri Feb 26 15:26:24 2021 +0000
+++ b/sipgen/sip.h	Mon Dec 06 12:26:46 2021 +0100
@@ -1631,6 +1631,7 @@
     const char *name;
     int use_arg_names;
     int use_limited_api;
+    int py_ssize_t_clean;
     int all_raise_py_exc;
     int call_super_init;
     const char *def_error_handler;