is not a valid codepoint

Description

Some functions uses integers to represents UTF-8 characters, on top of their string representation. When an integer is provided, it has to represent an actual character, in the UTF-8 range.

In particular, the character cannot be negative, or bigger than 55296.

Example

<?php

mb_substitute_character(-10);

?>

Solutions

• Check for the integer value before using it: it must be between 0 and 55296.

• Use a string representation, with an escape sequence.