Displays engine-level zval information, including reference counts for reference-counted types.
What It Does
var_dump() reports values, not internal reference-count details The function call itself affects reference counts; never treat the printed number as a stable application metric.
Requirements and Compatibility
Available in the PHP runtime; use PHP 8 or later for the shown typed, modern examples.
Syntax, Inputs and Results
The arguments shown below are concrete values for this function; their types and ranges matter. The example checks return data rather than assuming that every operation succeeds.
Example 1: Basic Use
Demonstrates the primary behavior.
<?php
$data = ['item' => 'notebook'];
$copy = $data;
debug_zval_dump($data);Example 2: Another Case
Handles an alternative input or use case.
<?php
$label = str_repeat('a', 12);
$second = $label;
debug_zval_dump($label, $second);Practical Example
Puts the function into a larger practical task.
<?php
$items = ['first' => 1];
$shared = $items;
$shared['second'] = 2;
debug_zval_dump($items);
print_r($shared);For production, apply the compatibility and edge-case limits described below.
Important Behavior and Edge Cases
The function call itself affects reference counts; never treat the printed number as a stable application metric.
Comparison with Related Functions and Tools
| Subject | Key difference |
|---|---|
| debug_zval_dump() | var_dump() reports values, not internal reference-count details |
Common Beginner Mistakes
| Mistake | Correct approach |
|---|---|
| Calling debug_zval_dump() without its required input or supported extension | Check the extension, supply valid arguments, and handle false or exceptions according to the function. |
| Assuming debug_zval_dump() guarantees a valid or safe image | Inspect the return and avoid exposing debug output to website visitors. |
| Confusing the operation with a related API | var_dump() reports values, not internal reference-count details |
Key Takeaways
- Displays engine-level zval information, including reference counts for reference-counted types.
- The function call itself affects reference counts; never treat the printed number as a stable application metric.
- Choose the companion API described in the comparison table when the job differs.
Use these examples as a starting point, then validate the result with the actual PHP build, dependencies and inputs used by your application.