The PHP Fiber::suspend API performs a focused operation on an object or value. The examples below show its effect on actual data.
Suspends the currently executing Fiber and optionally yields a value to its caller.
What Is Fiber::suspend in PHP?
Suspends the currently executing Fiber and optionally yields a value to its caller.
Syntax:
Fiber::suspend(mixed $value = ...): mixed
The method accepts the following parameters:
$value— Optional. The value to insert, store, or write; its accepted type depends on the underlying collection.
Return type declared by PHP: mixed. The value or side effect is demonstrated in the examples below.
Example 1: Basic Usage
This example uses a small input to make the main behavior visible.
<?php
$fiber = new Fiber(function (): string {
$input = Fiber::suspend("waiting");
return "completed: " . $input;
});
echo $fiber->start();
var_dump($fiber->isSuspended());
Output:
waitingbool(true)
Suspends the currently executing Fiber and optionally yields a value to its caller.
Example 2: A Different Input
A different set of values shows the same operation in another situation.
<?php
$fiber = new Fiber(function (): string {
$input = Fiber::suspend("request");
return "completed: " . $input;
});
echo $fiber->start();
var_dump($fiber->isSuspended());
Output:
requestbool(true)
A fiber must be suspended before resume() or throw(); getReturn() is available only after successful termination.
Practical Example: Applying the Feature
This example shows an application-style use of the feature, with its surrounding setup visible.
<?php
$fiber = new Fiber(function (): string {
$input = Fiber::suspend("pending");
return "completed: " . $input;
});
echo $fiber->start();
var_dump($fiber->isSuspended());
Output:
pendingbool(true)
The code is shown for learning. Adjust the class names, inputs and error handling to suit your application.
Important Behavior and Edge Cases
- A fiber must be suspended before resume() or throw(); getReturn() is available only after successful termination.
- Suspends the currently executing Fiber and optionally yields a value to its caller.
- Observe differences in empty inputs, invalid states and optional extension availability where relevant.
Comparison With Related Approaches
| Approach | Important Difference |
|---|---|
Fiber::suspend | Suspends the currently executing Fiber and optionally yields a value to its caller. |
| Generator | A Fiber suspends a whole call stack and supports resume() and throw(), while a Generator primarily yields sequence values. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
Ignoring the documented state or precondition of Fiber::suspend | A fiber must be suspended before resume() or throw(); getReturn() is available only after successful termination. |
| Expecting a different type of result | Read the declared return type and distinguish returned values from changes to the source object. |
| Assuming a related API works identically | A Fiber suspends a whole call stack and supports resume() and throw(), while a Generator primarily yields sequence values. |
Key Takeaways
- Suspends the currently executing Fiber and optionally yields a value to its caller.
- A fiber must be suspended before resume() or throw(); getReturn() is available only after successful termination.
- Use the example that matches the values, runtime version and dependencies in your application.
Fiber::suspend is useful when its behavior matches the data structure and lifecycle of your PHP application. Choose it with a clear understanding of its preconditions and returned values.