(PHP 4, PHP 5, PHP 7, PHP 8)
require 和 include
几乎完全一样，除了处理失败的方式不同之外。require
在出错时产生 E_COMPILE_ERROR
级别的错误。换句话说将导致脚本中止而 include
只产生警告（E_WARNING），脚本会继续运行。
参见 include 文档了解详情。
Remember, when using require that it is a statement, not a function. It's not necessary to write:
<?php
require('somefile.php');
?>
The following:
<?php
require 'somefile.php';
?>
Is preferred, it will prevent your peers from giving you a hard time and a trivial conversation about what require really is.If your included file returns a value, you can get it as a result from require(), i.e.
foo.php:
<?php
return "foo";
?>
$bar = require("foo.php");
echo $bar; // equals to "foo"Always use __DIR__ to define path relative to your current __FILE__.
(Or another setting that is originally based on __DIR__/__FILE__)
try & catch - don't get confused by the words "fatal E_COMPILE_ERROR" - it's still just an internal Error that implements Throwable - it can be caught:
<?php
try {
require(__DIR__ . '/something_that_does_not_exist');
} catch (\Throwable $e) {
echo "This was caught: " . $e->getMessage();
}
echo " End of script.";
?>
Note that this will still emit a warning "Failed to open stream: No such file or directory..." ...unless you prefix the require with "@" - which I strongly don't recommend as it would ignore/supress any diagnostic error (unless you have specified set_error_handler()). But even if you'd prefix the require with "@" it would still be caught.