在php中使用requires

echo需要php

return.php
<?php

$var = 'PHP';

return $var;

?>

noreturn.php
<?php

$var = 'PHP';

?>

testreturns.php
<?php

$foo = include 'return.php';

echo $foo; // prints 'PHP'

$bar = include 'noreturn.php';

echo $bar; // prints 1

?>

//$bar is the value 1 because the include was successful. Notice the difference between the above examples. The first uses return within the included file while the other does not. If the file can't be included, false is returned and E_WARNING is issued.