luaL_typerror

int luaL_typerror (lua_State *L, int narg, const char *tname);

Generates an error with a message like

     <location>: bad argument <narg> to <function> (<tname> expected, got <realt>)

where <location> is produced by luaL_where, <function> is the name of the current function, and <realt> is the type name of the actual argument.