require()
The require() statement includes and evaluates the specific file.
require() includes and evaluates a specific file. Detailed information on how this inclusion works is described in the documentation for include().
require() and include() are identical in every way except how they handle failure. They both produce a Warning, but require() results in a Fatal Error. In other words, don't hesitate to use require() if you want a missing file to halt processing of the page. include() does not behave this way, the script will continue regardless. Be sure to have an appropriate include_path setting as well.
Example#1 Basic require() examples
<?php
require 'prepend.php';
require $somefile;
require ('somefile.txt');
?>
See the include() documentation for more examples.
Note: Prior to PHP 4.0.2, the following applies: require() will always attempt to read the target file, even if the line it's on never executes. The conditional statement won't affect require(). However, if the line on which the require() occurs is not executed, neither will any of the code in the target file be executed. Similarly, looping structures do not affect the behaviour of require(). Although the code contained in the target file is still subject to the loop, the require() itself happens only once.
Note: Fordi dette er en indbygget sprogfunktion og ikke en funktion, kan den ikke blive kaldt vha. variable funktioner
Windows versioner af PHP før PHP 4.3.0 understøtter ikke adgang til fjernfiler via denne funktion, også selv om allow_url_fopen er slået til.
See also include(), require_once(), include_once(), get_included_files(), eval(), file(), readfile(), virtual() and include_path.