Two points worth noting:
1. fsync() is not suitable for high throughput, use it only when the durability of a file write really matters to you.
2. fsync() includes an implicit call to fflush() so you don't need to manually flush before you sync.
(PHP 8 >= 8.1.0)
fsync — Synchronizes changes to the file (including meta-data)
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.
streamВказівник на файл має бути дійсним та має вказувати на файл, успішно відкритий функцією fopen() або fsockopen() (та не закритий функцією fclose()).
Приклад #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);
?>
Two points worth noting:
1. fsync() is not suitable for high throughput, use it only when the durability of a file write really matters to you.
2. fsync() includes an implicit call to fflush() so you don't need to manually flush before you sync.