Question: I was searching for a specific topic but I found nothing that I was looking for.
I'm using a php code for logout the user:

```
    <?php
    if(!isset($_SESSION)) 
        { 
            session_start(); 
        } 
        session_unset();
        unset($_SESSION["id"]);
        unset($_SESSION["sign"]);
        unset($_SESSION["lang"]);
        unset($_SESSION["usertype"]);
        session_destroy();
        echo '<META HTTP-EQUIV="Refresh" CONTENT="0; URL=./index.php?lang=en">';
    ?>

```

And all is working fine except one annoying thing that I would like to avoid. When user presses a log-out button it can be observed that before initial page is shown the additional blank page appears for a while... Can this behaviour be eliminated? - I don't want to show anything in the meantime, I want to just redirect the user to a home page.

Answer: 
*From the comments above:*

`_Compare` is one of the template parameters of the `_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>` defined in that file, so surely it is defined. 

A more likely reason is that the Intel compiler perhaps doesn't know about `is_nothrow_move_assignable` which is kind of recently added to the type\_traits.
Well I checked with Intel agents and it turned out that Intel 16 do not support gcc6.3, the support comes in Intel 17.