trigger_error()

trigger_error() — Generates a user-level error/warning/notice message.

Built-in function of PHP 8.5. The manual lists it as available in PHP 4 >= 4.0.1, PHP 5, PHP 7, PHP 8. This page is the reference card: signature, parameters and return value, plus the changelog and the example the manual provides.

What it does

Used to trigger a user error condition, it can be used in conjunction with the built-in error handler, or with a user defined function that has been set as the new error handler (set_error_handler()).

Signature

trigger_error(string $message, int $error_level = E_USER_NOTICE): true

Parameters

Parameter	Type	What it takes
$message	string	The designated error message for this error. It's limited to 1024 bytes in length. Any additional characters beyond 1024 bytes will be truncated.
$error_level	int	The designated error type for this error. It only works with the E_USER_* family of constants, and will default to E_USER_NOTICE.

Return value

Always returns true.

Example

A runnable snippet:

$password = $_POST['password'] ?? ''; if ($password === '') { trigger_error("Using an empty password is unsafe", E_USER_WARNING); } $hash = password_hash($password, PASSWORD_DEFAULT);

Changelog

Version	Change
8.4.0	Passing E_USER_ERROR as the error_level is now deprecated. Throw an Exception or call exit() instead.
8.4.0	The function now has a return type of true instead of bool.
8.0.0	The function now throws a ValueError if an invalid error_level is specified. Previously, it returned false.