function set_rejection_handler

Sets the global rejection handler for unhandled promise rejections.

Note that rejected promises should always be handled similar to how any exceptions should always be caught in a `try` + `catch` block. If you remove the last reference to a rejected promise that has not been handled, it will report an unhandled promise rejection. See also the [`reject()` function](#reject) for more details.

The `?callable $callback` argument MUST be a valid callback function that accepts a single `Throwable` argument or a `null` value to restore the default promise rejection handler. The return value of the callback function will be ignored and has no effect, so you SHOULD return a `void` value. The callback function MUST NOT throw or the program will be terminated with a fatal error.

The function returns the previous rejection handler or `null` if using the default promise rejection handler.

The default promise rejection handler will log an error message plus its stack trace:

```php // Unhandled promise rejection with RuntimeException: Unhandled in example.php:2 React\Promise\reject(new RuntimeException('Unhandled')); ```

The promise rejection handler may be used to use customize the log message or write to custom log targets. As a rule of thumb, this function should only be used as a last resort and promise rejections are best handled with either the [`then()` method](#promiseinterfacethen), the [`catch()` method](#promiseinterfacecatch), or the [`finally()` method](#promiseinterfacefinally). See also the [`reject()` function](#reject) for more details.

Parameters

callable(\Throwable):void|null $callback:

Return value

callable(\Throwable):void|null

1 call to set_rejection_handler()

RejectedPromise::__destruct in vendor/react/promise/src/Internal/RejectedPromise.php

File

vendor/react/promise/src/functions.php, line 255

Namespace

React\Promise

Code

function set_rejection_handler(?callable $callback) : ?callable {
    static $current = null;
    $previous = $current;
    $current = $callback;
    return $previous;
}