PHP Australia Conference 2015

return

(PHP 4, PHP 5)

return retourne le contrôle du programme au module appelant. L'exécution reprend alors à l'endroit de l'invocation du module.

Si appelée depuis une fonction, la commande return termine immédiatement la fonction, et retourne l'argument qui lui est passé. return interrompt aussi l'exécution de commande eval() ou de scripts.

Si appelée depuis l'environnement global, l'exécution du script est interrompue. Si le script courant était inclus avec la structure include ou require, alors le contrôle est rendu au script appelant. De plus, si le fichier du script courant a été inclus via l'instruction include, alors la valeur retournée sera utilisée comme résultat de l'instruction include. Si return est appelée depuis le script principal, alors l'exécution du script s'arrête. Si le script courant est auto_prepend_file ou auto_append_file dans le fichier php.ini, alors l'exécution du script s'arrête.

Pour plus d'informations, voyez retourner des valeurs.

Note: Notez que puisque return est une structure de langage, et non une fonction, les parenthèses entourant les arguments ne sont pas nécessaires. Il est classique de les oublier et vous devriez le faire car PHP travaillera moins dans ce cas.

Note: Si aucun paramètre n'est fourni, alors les parenthèses peuvent être omises et NULL sera retourné. L'appel à la fonction return avec des parenthèses mais sans argument résultera en une alerte d'analyse.

Note: Vous ne devriez jamais utiliser les parenthèses autour de la variable retournée lorsque vous la retournez pas référence, car cela ne fonctionnera pas. Vous ne pouvez retourner que les variables par référence, et non le résultat du traitement. Si vous utilisez return ($a);, alors vous ne retournez pas une variable mais le résultat de l'expression ($a) (qui est, bien sûr, la valeur de $a).

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User Contributed Notes 4 notes

up
18
warhog at warhog dot net
8 years ago
for those of you who think that using return in a script is the same as using exit note that: using return just exits the execution of the current script, exit the whole execution.

look at that example:

a.php
<?php
include("b.php");
echo
"a";
?>

b.php
<?php
echo "b";
return;
?>

(executing a.php:) will echo "ba".

whereas (b.php modified):

a.php
<?php
include("b.php");
echo
"a";
?>

b.php
<?php
echo "b";
exit;
?>

(executing a.php:) will echo "b".
up
12
Tom
7 months ago
Keep in mind that even if PHP allows you to use "return" in the global scope it is very bad design to do so.

Using the return statement in the global scope encourages programmers to use files like functions and treat the include-statement like a function call. Where they initialize the file's "parameters" by setting variables in the global scope and reading them in the included file.

Like so: (WARNING! This code was done by professionals in a controlled environment. Do NOT try this at home!)
<?php
$parameter1
= "foo";
$parameter2 = "bar";
$result = include "voodoo.php";
?>

Where "voodoo.php" may be something like:
<?php
return $parameter1 . " " . $parameter2;
?>

This is one of the worst designs you can implement since there is no function head, no way to understand where $parameter1 and $parameter2 come from by just looking at "voodoo". No explanation in the calling file as of what $parameter1 and -2 are doing or why they are even there. If the names of the parameters ever change in "voodoo" it will break the calling file. No IDE will properly support this very poor "design". And I won't even start on the security issues!

If you find yourself in a situation where a return-statement in global scope is the answer to your problem, then maybe you are asking the wrong questions. Actually you may be better off using a function and throwing an exception where needed.

Files are NOT functions. They should NOT be treated as such and under no circumstances should they "return" anything at all.

Remember: Every time you abuse a return statement God kills a kitten and makes sure you are reborn as a mouse!
up
5
J.D. Grimes
1 year ago
Note that because PHP processes the file before running it, any functions defined in an included file will still be available, even if the file is not executed.

Example:

a.php
<?php
include 'b.php';

foo();
?>

b.php
<?php
return;

function
foo() {
     echo
'foo';
}
?>

Executing a.php will output "foo".
up
-10
andrew at neonsurge dot com
6 years ago
Response to stoic's message below...

I believe the way you've explained this for people may be a bit confusing, and your verbiage is incorrect.  Your script below is technically calling return from a global scope, but as it says right after that in the description above... "If the current script file was include()ed or require()ed, then control is passed back to the calling file".  You are in a included file.  Just making sure that is clear.

Now, the way php works is before it executes actual code it does what you call "processing" is really just a syntax check.  It does this every time per-file that is included before executing that file.  This is a GOOD feature, as it makes sure not to run any part of non-functional code.  What your example might have also said... is that in doing this syntax check it does not execute code, merely runs through your file (or include) checking for syntax errors before execution.  To show that, you should put the echo "b"; and echo "a"; at the start of each file.  This will show that "b" is echoed once, and then "a" is echoed only once, because the first time it syntax checked a.php, it was ok.  But the second time the syntax check failed and thus it was not executed again and terminated execution of the application due to a syntax error.

Just something to help clarify what you have stated in your comments.
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