fdatasync()
fdatasync() — Synchronizes data (but not meta-data) to the file.
Built-in function of PHP 8.5. The manual lists it as available in PHP 8 >= 8.1.0. This page is the reference card: signature, parameters and return value, plus the changelog and the example the manual provides.
What it does
This function synchronizes stream contents to storage media, just like fsync() does, but it does not synchronize file meta-data. Note that this function is only effectively different in POSIX systems. In Windows, this function is aliased to fsync().
Signature
fdatasync(resource $stream): bool
Parameters
| Parameter | Type | What it takes |
|---|---|---|
| $stream | resource | The file pointer must be valid, and must point to a file successfully opened by fopen() or fsockopen() (and not yet closed by fclose()). |
Return value
Returns true on success or false on failure.
Example
A runnable snippet:
$file = 'test.txt'; $stream = fopen($file, 'w'); fwrite($stream, 'test data'); fwrite($stream, "\r\n"); fwrite($stream, 'additional data'); fdatasync($stream); fclose($stream);
See also
All PHP 8.5 built-in functions
Reference card built from the PHP manual page fdatasync() (PHP documentation, CC BY 3.0). The page is generated from the manual, so the wording of the parameter and return value text follows php.net.