07 Jul PHP Constants

A constant once defined, cannot be undefined. A valid constant name starts with a letter or underscore (no $ sign before the constant name). PHP constants use the define() function for creating a constant.

Constant name starts with a letter or underscore, but they can’t be considered as a variable, since constant name once defined can’t be changed.

The define() function is used for creating a constant. Here’s the syntax:

Here,

• name is the constant name
• val is the value of the constant
• case-insensitive is for constant name insensitive.

The following is an example:

Here’s the output,

In the above example, we haven’t mentioned the case section, since the default is false. If you want a case-insensitive name, use true i.e

We used the define() function since it is used for creating a constant.