Content · Programming · PHP

PHP Fiber::isTerminated() Method: Usage and Examples

PHP Fiber::isTerminated() Method: Usage and Examples: Reports whether the Fiber has completed execution. See three examples and important limitations.

1 views Published Oct 17, 2026 Updated Oct 17, 2026 Know-Stuff

The PHP Fiber::isTerminated API performs a focused operation on an object or value. The examples below show its effect on actual data.

Reports whether the Fiber has completed execution.

What Is Fiber::isTerminated in PHP?


Reports whether the Fiber has completed execution.

Syntax:

Fiber::isTerminated(): bool

This operation has no parameters.

Return type declared by PHP: bool. 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;
});
$fiber->start();
$fiber->resume("approved");
var_dump($fiber->isTerminated());

Output:

bool(true)

Reports whether the Fiber has completed execution.

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;
});
$fiber->start();
$fiber->resume("accepted");
var_dump($fiber->isTerminated());

Output:

bool(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;
});
$fiber->start();
$fiber->resume("verified");
var_dump($fiber->isTerminated());

Output:

bool(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.
  • Reports whether the Fiber has completed execution.
  • Observe differences in empty inputs, invalid states and optional extension availability where relevant.

Comparison With Related Approaches


ApproachImportant Difference
Fiber::isTerminatedReports whether the Fiber has completed execution.
GeneratorA Fiber suspends a whole call stack and supports resume() and throw(), while a Generator primarily yields sequence values.

Common Beginner Mistakes


MistakeCorrect Approach
Ignoring the documented state or precondition of Fiber::isTerminatedA fiber must be suspended before resume() or throw(); getReturn() is available only after successful termination.
Expecting a different type of resultRead the declared return type and distinguish returned values from changes to the source object.
Assuming a related API works identicallyA Fiber suspends a whole call stack and supports resume() and throw(), while a Generator primarily yields sequence values.

Key Takeaways


  • Reports whether the Fiber has completed execution.
  • 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::isTerminated 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.

Share this resourceSend this page to someone who may find it useful.