PHP: Hypertext Preprocessor (original) (raw)
require_once
(PHP 4, PHP 5, PHP 7, PHP 8)
The require_once expression is identical torequire except PHP will check if the file has already been included, and if so, not include (require) it again.
See the include_once documentation for information about the _once behaviour, and how it differs from its non _once siblings.
Found A Problem?
14 years ago
`If your code is running on multiple servers with different environments (locations from where your scripts run) the following idea may be useful to you:
a. Do not give absolute path to include files on your server.
b. Dynamically calculate the full path (absolute path)
Hints:
Use a combination of dirname(FILE) and subsequent calls to itself until you reach to the home of your '/index.php'. Then, attach this variable (that contains the path) to your included files.
One of my typical example is:
instead of:
After this, if you copy paste your codes to another servers, it will still run, without requiring any further re-configurations.
[EDIT BY danbrown AT php DOT net: Contains a typofix (missing ')') provided by 'JoeB' on 09-JUN-2011.]
`
bobray99 at softville dot com ¶
3 years ago
`Be careful when using include_once and require_once for files that return a value:
fiddle2.php
<?php
return "Some String";fiddle.php
<?php
$s = require_once('fiddle2.php');
echo "\n" . $s;
$s = require_once('fiddle2.php');
echo "\n" . $s;/* output
Some String
1
*/The second time require_once occurs, it returns 1 because the file has already been included.
`
boda0128318 at gmail dot com ¶
4 years ago
`1 - "require" and "require_once" throw a fatal error if the file is not
existing and stop the script execution
2 - "include" and "include_once" throw a warning and the execution
continues
3 - "require_once" and "include_once" as their names suggests ,
they will not include the file if the file was already included with
"require", "require_once", "include" or "include_once"
try the following code:
create a file called "index.php"
and another file that is called "first.php" and write the following header
Hello every one
i hope this will help you
`
operator at juliyvchirkov dot dev ¶
10 days ago
`My five cents to the note by bimal at sanjaal dot com
One should avoid the common pitfall with construct especially when it is about examples in PHP manual.
Please consider to use either or instead and update your note accordingly.
`
9 years ago
"require_once" and "require" are language constructs and not functions. Therefore they should be written without "()" brackets!