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<fstatftell>
^Filesystem FunctionsLast updated: Mon, 26 Oct 2026

fsync

(PHP 8 >= 8.1.0)

fsync — Synchronizes changes to the file (including meta-data)

Description

function fsync(resource $stream): bool

This function synchronizes changes to the file, including its meta-data. This is similar to fflush(), but it also instructs the operating system to write to the storage media.

Parameters

stream

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 Values

Returns true on success or false on failure.

Examples

Example #1 fsync() example

<?php

$file = 'test.txt';

$stream = fopen($file, 'w');
fwrite($stream, 'test data');
fwrite($stream, "\r\n");
fwrite($stream, 'additional data');

fsync($stream);
fclose($stream);
?>

See Also

  • fdatasync() - Synchronizes data (but not meta-data) to the file
  • fflush() - Flushes the output to a file


<fstatftell>
^Filesystem FunctionsLast updated: Mon, 26 Oct 2026