Understanding PHP's case-sensitivity

PHP functions and methods

In PHP, classes, functions and methods are case-insensitive. That is:

// Class
$x = new User_Tag();
$x = NEW USeR_tAG();

// Methods

// Functions

All are OK and compile fine, and behave identically. This is largely a problem only when needing to ensure case for class loading in file systems which are case sensistive (the majority of servers where PHP runs).

Includes and Files

Whether file paths are case-sensitive or not, unfortunately, depends greatly on the platform (Mac OX S, Windows, UNIX), and particularly the file system settings. On the following platforms, file names are case-insensitive (in general):

On Unix variants such as Linux-kernel Operating Systems, *BSDs, etc. files are generally case sensitive.

Paths and directory delimiter

On Unix and Mac OS X, the forward slash "/" is generally used as the DIRECTORY-SEPARATOR, while on Windows the backslash "\" is used. So:

/app/vendor/zesk/zesk/autoload.php # Unix
C:\app\vendor\zesk\zesk\autoload.php # Windows

Note that Windows uses the colon ":" as the first portion of the path to identify the drive letter.