The `addcslashes()` string function in PHP 8.4 adds backslashes before specified characters in a string, formatting them in a C-style representation. This is particularly useful for escaping characters that have special meanings in contexts like C programming or for preparing strings for certain outputs.

Syntax:

<?php
addcslashes(string $string, string $characters): string
?>

`$string`: The input string.
`$characters`: A list of characters to be escaped.

Examples:

Escaping Specific Characters:

<?php
$string = "Hello, World!";
// Escape the character 'W'
$escapedString = addcslashes($string, 'W');
echo $escapedString; // Output: Hello, \World!
?>

In this example, the character ‘W’ is escaped with a backslash.