From Lua 5.2: Add luaL_testudata().

Contributed by François Perrad.
eugeneia · Apr 7, 2017 · cde968f · cde968f
1 parent f2e2a3f
commit cde968f
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Showing 2 changed files with 10 additions and 3 deletions.
diff --git a/src/lauxlib.h b/src/lauxlib.h
@@ -88,6 +88,7 @@ LUALIB_API void luaL_traceback (lua_State *L, lua_State *L1, const char *msg,
 LUALIB_API void (luaL_setfuncs) (lua_State *L, const luaL_Reg *l, int nup);
 LUALIB_API void (luaL_pushmodule) (lua_State *L, const char *modname,
  int sizehint);
+LUALIB_API void *(luaL_testudata) (lua_State *L, int ud, const char *tname);
 
 
 /*

diff --git a/src/lj_api.c b/src/lj_api.c
@@ -875,7 +875,7 @@ LUA_API void lua_upvaluejoin(lua_State *L, int idx1, int n1, int idx2, int n2)
  lj_gc_objbarrier(L, fn1, gcref(fn1->l.uvptr[n1]));
 }
 
-LUALIB_API void *luaL_checkudata(lua_State *L, int idx, const char *tname)
+LUALIB_API void *luaL_testudata(lua_State *L, int idx, const char *tname)
 {
  cTValue *o = index2adr(L, idx);
  if (tvisudata(o)) {
@@ -884,8 +884,14 @@ LUALIB_API void *luaL_checkudata(lua_State *L, int idx, const char *tname)
  if (tv && tvistab(tv) && tabV(tv) == tabref(ud->metatable))
  return uddata(ud);
  }
- lj_err_argtype(L, idx, tname);
- return NULL; /* unreachable */
+ return NULL; /* value is not a userdata with a metatable */
+}
+
+LUALIB_API void *luaL_checkudata(lua_State *L, int idx, const char *tname)
+{
+ void *p = luaL_testudata(L, idx, tname);
+ if (!p) lj_err_argtype(L, idx, tname);
+ return p;
 }
 
 /* -- Object setters ------------------------------------------------------ */