WordPress at a glance
function is not described

WP_Filesystem() WP 2.5.0

Initialises and connects the WordPress Filesystem Abstraction classes. This function will include the chosen transport and attempt connecting.

Plugins may add extra transports, And force WordPress to use them by returning the filename via the 'filesystem_method_file' filter.

  • Global. WP_Filesystem_Base. $wp_filesystem Subclass
Hooks in function
Return

null/true/false. false on failure, true on success.

Usage

WP_Filesystem( $args, $context, $allow_relaxed_file_ownership );
$args(array/false)
Connection args, These are passed directly to the WP_Filesystem_*() classes.
Default: false
$context(string/false)
Context for get_filesystem_method().
Default: false
$allow_relaxed_file_ownership(true/false)
Whether to allow Group/World writable.
Default: false

Code of WP Filesystem: wp-admin/includes/file.php VER 5.0.3

<?php
function WP_Filesystem( $args = false, $context = false, $allow_relaxed_file_ownership = false ) {
	global $wp_filesystem;

	require_once(ABSPATH . 'wp-admin/includes/class-wp-filesystem-base.php');

	$method = get_filesystem_method( $args, $context, $allow_relaxed_file_ownership );

	if ( ! $method )
		return false;

	if ( ! class_exists( "WP_Filesystem_$method" ) ) {

		/**
		 * Filters the path for a specific filesystem method class file.
		 *
		 * @since 2.6.0
		 *
		 * @see get_filesystem_method()
		 *
		 * @param string $path   Path to the specific filesystem method class file.
		 * @param string $method The filesystem method to use.
		 */
		$abstraction_file = apply_filters( 'filesystem_method_file', ABSPATH . 'wp-admin/includes/class-wp-filesystem-' . $method . '.php', $method );

		if ( ! file_exists($abstraction_file) )
			return;

		require_once($abstraction_file);
	}
	$method = "WP_Filesystem_$method";

	$wp_filesystem = new $method($args);

	//Define the timeouts for the connections. Only available after the construct is called to allow for per-transport overriding of the default.
	if ( ! defined('FS_CONNECT_TIMEOUT') )
		define('FS_CONNECT_TIMEOUT', 30);
	if ( ! defined('FS_TIMEOUT') )
		define('FS_TIMEOUT', 30);

	if ( is_wp_error($wp_filesystem->errors) && $wp_filesystem->errors->get_error_code() )
		return false;

	if ( !$wp_filesystem->connect() )
		return false; //There was an error connecting to the server.

	// Set the permission constants if not already set.
	if ( ! defined('FS_CHMOD_DIR') )
		define('FS_CHMOD_DIR', ( fileperms( ABSPATH ) & 0777 | 0755 ) );
	if ( ! defined('FS_CHMOD_FILE') )
		define('FS_CHMOD_FILE', ( fileperms( ABSPATH . 'index.php' ) & 0777 | 0644 ) );

	return true;
}