PHP clearstatcache() Function

PHP clearstatcache Function


Definition :

The PHP clearstatcache() function clears the file status cache.

PHP caches the information in order to provide faster performance. However, in certain cases, clearing the cached information is required. For example, if the same file is being checked multiple times within a single script, you probably want to avoid caching to get correct results. In these cases, clearstatcache() function is used to clear the information that PHP caches about a file.

The affected functions from this function include:

  • stat()
  • lstat()
  • file_exists()
  • is_writable()
  • is_readable()
  • is_executable()
  • is_file()
  • is_dir()
  • is_link()
  • filectime()
  • fileatime()
  • filemtime()
  • fileinode()
  • filegroup()
  • fileowner()
  • filesize()
  • filetype()
  • fileperms()
Syntax

   clearstatcache(clear_realpath_cache, filename)

Parameter 
Parameter Description
clear_realpath_cache Optional. Indicates whether to clear the realpath cache or not. Default is FALSE, which indicates not to clear realpath cache
filename Optional. Specifies a filename, and clears the realpath and cache for that file only
Example:

Lets assume that we have a file called test.txt. This file contains following content:

This is a test file.
It contains dummy content.

In the example below, size of the file is returned at three different stages: initial, after performing write operation and after clearing file status cache. During write operation, the size of the file gets changed. To get the changed file size, clearstatcache() function is used which clears the file status cache.

\

Output :  

Initial size: 48 bytes
After write operation: 48 bytes
After clearing cache: 25 bytes