Returns the Zend Engine version embedded in the current PHP runtime.
What It Does and When to Use It
Display the engine version independently from the PHP release version. A minimum platform requirement controls what syntax can be parsed; target-version tests find runtime and extension incompatibilities.
Requirements, Inputs and Expected Behavior
Confirm the runtime, extension, environment variables, and permissions before running the examples in production. The Zend version differs from PHP_VERSION and must not be used for package constraints.
Example 1: Basic Operation
Display the engine version independently from the PHP release version.
<?php
echo zend_version();Example 2: Behavior and Validation
Illustrate why engine version and runtime version differ.
<?php
echo 'PHP: ', PHP_VERSION, '; Zend Engine: ', zend_version();Practical Example: Application Use
Include both values in a diagnostic report without treating them as interchangeable.
<?php
$info = ['php' => PHP_VERSION, 'zend' => zend_version(), 'sapi' => PHP_SAPI];
echo json_encode($info, JSON_THROW_ON_ERROR);Important Behavior and Edge Cases
The second example highlights: Illustrate why engine version and runtime version differ. The practical example adds: Include both values in a diagnostic report without treating them as interchangeable.
Comparison with Related Approaches
| Approach | What changes |
|---|---|
| Minimum PHP version and target PHP version | A minimum platform requirement controls what syntax can be parsed; target-version tests find runtime and extension incompatibilities. |
| Choosing safely | Do not introduce syntax from a newer minor version before every production host supports it. |
Common Beginner Mistakes
| Mistake | Correct approach |
|---|---|
| Assuming newer syntax parses on older PHP | Lint with the oldest supported runtime; gate or delay newer syntax. |
| Upgrading CLI PHP but not the web worker | Check the FPM binary, all extensions and the Composer platform in staging. |
| Skipping operational constraints | The Zend version differs from PHP_VERSION and must not be used for package constraints. |
Key Takeaways
- Returns the Zend Engine version embedded in the current PHP runtime.
- Include both values in a diagnostic report without treating them as interchangeable.
- Do not introduce syntax from a newer minor version before every production host supports it.