diff --git a/psycopg/connection_type.c b/psycopg/connection_type.c
index f531113e..ca61a7fd 100644
--- a/psycopg/connection_type.c
+++ b/psycopg/connection_type.c
@@ -112,10 +112,10 @@ psyco_conn_cursor(connectionObject *self, PyObject *args, PyObject *kwargs)
         goto exit;
     }
 
-    if (0 != psyco_curs_withhold_set((cursorObject *)obj, withhold)) {
+    if (0 > psyco_curs_withhold_set((cursorObject *)obj, withhold)) {
         goto exit;
     }
-    if (0 != psyco_curs_scrollable_set((cursorObject *)obj, scrollable)) {
+    if (0 > psyco_curs_scrollable_set((cursorObject *)obj, scrollable)) {
         goto exit;
     }
 
diff --git a/psycopg/cursor.h b/psycopg/cursor.h
index d89bf219..300b8916 100644
--- a/psycopg/cursor.h
+++ b/psycopg/cursor.h
@@ -93,8 +93,8 @@ struct cursorObject {
 /* C-callable functions in cursor_int.c and cursor_type.c */
 BORROWED HIDDEN PyObject *curs_get_cast(cursorObject *self, PyObject *oid);
 HIDDEN void curs_reset(cursorObject *self);
-HIDDEN int psyco_curs_withhold_set(cursorObject *self, PyObject *pyvalue);
-HIDDEN int psyco_curs_scrollable_set(cursorObject *self, PyObject *pyvalue);
+RAISES_NEG HIDDEN int psyco_curs_withhold_set(cursorObject *self, PyObject *pyvalue);
+RAISES_NEG HIDDEN int psyco_curs_scrollable_set(cursorObject *self, PyObject *pyvalue);
 HIDDEN PyObject *psyco_curs_validate_sql_basic(cursorObject *self, PyObject *sql);
 
 /* exception-raising macros */
diff --git a/psycopg/cursor_type.c b/psycopg/cursor_type.c
index 591f5b32..e6368247 100644
--- a/psycopg/cursor_type.c
+++ b/psycopg/cursor_type.c
@@ -1681,7 +1681,7 @@ psyco_curs_withhold_get(cursorObject *self)
     return PyBool_FromLong(self->withhold);
 }
 
-int
+RAISES_NEG int
 psyco_curs_withhold_set(cursorObject *self, PyObject *pyvalue)
 {
     int value;
@@ -1726,7 +1726,7 @@ psyco_curs_scrollable_get(cursorObject *self)
     return ret;
 }
 
-int
+RAISES_NEG int
 psyco_curs_scrollable_set(cursorObject *self, PyObject *pyvalue)
 {
     int value;