PHP - Direct I/O dio_truncate() Function

---

---

The PHP Direct I/O dio_truncate() function is used to truncate (shorten) a file to a given length. It means that the file can get smaller if the content is removed after a set period of time.

Syntax

Below is the syntax of the PHP Direct I/O dio_truncate() function −

bool dio_truncate (resource $fd, int $length)

Parameters

Below are the parameters of the dio_truncate() function −

• $fd − It is a resource that is typically obtained using dio_open().

• $length − It is the length to which the file should be truncated. This is an integer.

Return Value

The dio_truncate() function returns TRUE on success and FALSE on failure.

PHP Version

First introduced in core PHP 4.3.0, the dio_truncate() function continues to function easily in PHP 5.1.0.

Example 1

First we will show you the basic example of the PHP Direct I/O dio_truncate() function to open a file and truncate it to 10 bytes.

<?php
   // Open a file descriptor
   $fd = dio_open('/PHP/PhpProjects/myfile.txt', O_RDWR);
   if ($fd) {
       dio_truncate($fd, 10);
       dio_close($fd);
   }
   echo "The file is truncated successfully!";
?>

Output

The above code will result something like this −

The file is truncated successfully!

Example 2

In the below PHP code we will try to use the dio_truncate() function and we truncate a file to zero bytes by emptying it.

<?php
   // Open a file descriptor
   $fd = dio_open('/PHP/PhpProjects/sample.txt', O_RDWR);
   if ($fd) {
       dio_truncate($fd, 0);
       dio_close($fd);
   }
   
   echo "Truncated a File to Zero Bytes";
?> 

Output

After running the above program, it generates the following output −

Truncated a File to Zero Bytes

Example 3

Now the below code to handle errors when truncating a file using the dio_truncate() function, and prints the error message.

<?php
   // Open a file descriptor
   $fd = dio_open('/PHP/PhpProjects/newfile.txt', O_RDWR);
   if ($fd) {
       if (!dio_truncate($fd, 10)) {
           echo "Error truncating file";
       }
       dio_close($fd);
   } else {
       echo "Error opening file";
   }
?> 

Output

This will create the below output −

Error truncating file