Requests that file data be synchronized from buffers to persistent storage.
What Is fdatasync() in PHP?
Requests that file data be synchronized from buffers to persistent storage.
Its syntax is:
fdatasync(resource $stream): boolParameters:
$stream— Accepted as resource; required argument.
Return type: bool. Requires a suitable writable file stream. Synchronization does not make a multi-step transaction atomic.
Availability: Available in PHP 8.1+; stream and filesystem support vary.
Example 1: Basic Usage
<?php
$stream = tmpfile(); fwrite($stream, "report"); var_dump(fdatasync($stream)); fclose($stream);
Result: Results and availability depend on the current PHP process, system permissions, cache, filesystem or installed locale. Requires a suitable writable file stream. Synchronization does not make a multi-step transaction atomic.
Example 2: A Different Input
<?php
$stream = tmpfile(); fwrite($stream, "hello"); fflush($stream); echo fdatasync($stream) ? "Synced" : "Failed"; fclose($stream);
Result: Results and availability depend on the current PHP process, system permissions, cache, filesystem or installed locale. Requires a suitable writable file stream. Synchronization does not make a multi-step transaction atomic.
Practical Example: Applying It in a Program
<?php
$stream = tmpfile(); fwrite($stream, "invoice-data"); if (!fdatasync($stream)) { echo "Unable to sync data"; } else { echo "Data sync requested"; } fclose($stream);
Result: Results and availability depend on the current PHP process, system permissions, cache, filesystem or installed locale. Requires a suitable writable file stream. Synchronization does not make a multi-step transaction atomic.
Important Behavior and Edge Cases
- Key behavior: Requires a suitable writable file stream. Synchronization does not make a multi-step transaction atomic.
- Environment: Available in PHP 8.1+; stream and filesystem support vary.
Comparison With Related Functions
| Function | Purpose |
|---|---|
fdatasync() | Requests that file data be synchronized from buffers to persistent storage. |
fsync() | fsync() asks to synchronize file data and metadata; fdatasync() concentrates on data and required metadata. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
| Ignoring this behavior: Requires a suitable writable file stream | Requires a suitable writable file stream. Synchronization does not make a multi-step transaction atomic. |
Key Takeaways
- Requests that file data be synchronized from buffers to persistent storage.
- Requires a suitable writable file stream. Synchronization does not make a multi-step transaction atomic.
- Available in PHP 8.1+; stream and filesystem support vary.
Summary: Requires a suitable writable file stream. Synchronization does not make a multi-step transaction atomic.