# Defined constants

Constant definitions will be done at the very beginning of an entry script on separated file `index.consist.php` inside skeleton application. constants are separated for specific cases that you want extend Poirot beside other frameworks and scripts so by include this file whole constant, environment and directory structure could be revealed to other systems.

### What Are These Constants?

| Constant Name                | Description                                                                                                                                                                                                                                                 | Could Overrides? |
| ---------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------- |
| **DS**                       | Current system directory separator                                                                                                                                                                                                                          | *No*             |
| **TIME\_REQUEST\_MICRO**     | Micro time script started up                                                                                                                                                                                                                                | *No*             |
| **PT\_DIR\_SKELETON**        | Path address point to skeleton package directory.                                                                                                                                                                                                           | *No*             |
| **PT\_DIR\_CONFIG\_INITIAL** | Path Address to initial system configurations directory. *configuration files inside this directory can be overrides by config load mechanism.*                                                                                                             | *No*             |
| **PT\_DIR\_ROOT**            | Path address meant to be a directory root of projects where we have .env files html public directory and vendor by default.                                                                                                                                 | *Yes*            |
| **PT\_DIR\_CONFIG**          | <p>Path Address to where we store additional configuration files to override application or modules default.</p><p><strong>Default Value:</strong> <code>PT\_DIR\_SKELETON/config/</code></p>                                                               | *Yes*            |
| **PT\_DIR\_DATA**            | <p>Path Address to where we meant to store run-time application data.</p><p><strong>Default Value:</strong> <code>PT\_DIR\_SKELETON/data/</code></p>                                                                                                        | *Yes*            |
| **PT\_DIR\_TMP**             | <p>Path Address to where we meant to store application temporary data.<br>based on the environment and OS you could replace the default value for exp. to /tmp on linux systems. </p><p><strong>Default Value:</strong> <code>PT\_DIR\_DATA/tmp/</code></p> | *Yes*            |
| **PT\_DIR\_CORE**            | <p>Path Address to Core modules, basically it's a directory where we put core modules of skeleton application.</p><p></p><p><strong>Default Value:</strong> <code>PT\_DIR\_SKELETON/src/core</code></p>                                                     | *Yes*            |
| **PT\_DIR\_VENDOR**          | <p>Directory path to vendors</p><p><strong>Default Value:</strong> <code>PT\_DIR\_ROOT/vendors/</code></p>                                                                                                                                                  | *Yes*            |

You could also read about Directory Structure and use cases that why it's needed on this page.

{% content-ref url="directory-skeleton" %}
[directory-skeleton](https://poirot-framework.gitbook.io/poirot/getting-started/directory-skeleton)
{% endcontent-ref %}

Continue reading to next section