--- lposix.c.old	2007-07-16 21:51:40.000000000 +0800
+++ lposix.c	2007-07-16 21:54:01.000000000 +0800
@@ -64,8 +64,7 @@
 	}
 	else
 	{
-		int j=luaL_findstring(luaL_checkstring(L, i), S);
-		if (j==-1) luaL_argerror(L, i, "unknown selector");
+		int j=luaL_checkoption(L, i, NULL, S);
 		return F(L, j, data);
 	}
 }