Question: I recently wrote a C program that is supposed to run in a Linux environment as follows;

```
#include <stdio.h>
#include <stdlib.h>

void main()
{
    system("notify-send -u normal -t 200 'You Have received a new message'");
    system("cvlc /home/ashenafis/Music/BabyMessage.mp3");
    return 0;
}

```

Compiled it and saved the executable in "/usr/sbin/play".

When I run it from the terminal it works fine, however it does not work when I try to run it from a PHP script using

```
<?php exec("/usr/sbin/play"); ?>

```

Is there something I am missing? Please help.

Answer: 
You can include the browser in the sequence diagram but you should not include UI details. You should just have the requests that can be initiated via the browser. This diagram is a good example:

<http://click.apache.org/docs/user-guide/htmlsingle/images/ajax/ajax-request-sequence-diagram.png>
YES, it is. But, it can be a business logic object and a interface / GUI object, at the same time.

You could, separate the logic and the interface code into different classes / objects.