PHP | SplFileObject ftruncate() Function

Last Updated : 11 Jul, 2025
The SplFileObject::ftruncate() function is an inbuilt function of Standard PHP Library (SPL) in PHP which is used to truncates the file size in bytes. Syntax: 
bool SplFileObject::ftruncate( $length )
Parameters: This function accept single parameter $length which specified the length of truncate of the file. Return values: This function returns True on success or False on failure. Below Programs illustrate the SplFileObject ftruncate() function in PHP: Program 1: php 
<?php

// Create a file named "gfg.txt" which
// containing data "GeeksforGeeks"
$gfg = new SplFileObject("gfg.txt", "w+");
$gfg->fwrite("GeeksforGeeks");

// Truncate file 
$gfg->ftruncate(8);

// Rewind and reading data from file
$gfg->rewind();

// Print result after truncate
echo $gfg->fgets();
?>
Output: 
Geeksfor
Program 2: php 
<?php
 
// Create an Array
$GFG = array(
    "dummy.txt",
    "gfg.txt",
    "frame.txt"
    );
 
// Creating Spl Object
foreach ($GFG as &$arr) {
    $file = new SplFileObject($arr);
     
    // Truncate file 
    $file->ftruncate(8);
     
    // Rewind and reading data from file
    $file->rewind();
     
    // Print result after truncate
    echo $file->fgets();
}
?>
Output: 
Geeksfor
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Reference: https://www.php.net/manual/en/splfileobject.ftruncate.php
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