diff --git a/lapi.c b/lapi.c
index 0ea3dc0f..ffc4d5e5 100644
--- a/lapi.c
+++ b/lapi.c
@@ -350,23 +350,21 @@ LUA_API size_t lua_stringtonumber (lua_State *L, const char *s) {
 
 
 LUA_API lua_Number lua_tonumberx (lua_State *L, int idx, int *pisnum) {
-  lua_Number n;
+  lua_Number n = 0;
   const TValue *o = index2value(L, idx);
   int isnum = tonumber(o, &n);
-  if (!isnum)
-    n = 0;  /* call to 'tonumber' may change 'n' even if it fails */
-  if (pisnum) *pisnum = isnum;
+  if (pisnum)
+    *pisnum = isnum;
   return n;
 }
 
 
 LUA_API lua_Integer lua_tointegerx (lua_State *L, int idx, int *pisnum) {
-  lua_Integer res;
+  lua_Integer res = 0;
   const TValue *o = index2value(L, idx);
   int isnum = tointeger(o, &res);
-  if (!isnum)
-    res = 0;  /* call to 'tointeger' may change 'n' even if it fails */
-  if (pisnum) *pisnum = isnum;
+  if (pisnum)
+    *pisnum = isnum;
   return res;
 }