return

(PHP 4, PHP 5)

Si se llama desde una función, la sentencia return inmediatamente termina la ejecución de la función actual, y devuelve su argumento como el valor de la llamada a la función. return también pondrá fin a la ejecución de una sentencia eval() o a un archivo de script.

Si se llama desde el ámbito global, entonces la ejecución del script actual se termina. Si el archivo script actual fue incluido o requerido con include o require, entonces el control es pasado de regreso al archivo que hizo el llamado. Además, si el archivo script actual fue incluido con include, entonces el valor dado a return será retornado como el valor de la llamada include. Si return es llamado desde dentro del fichero del script principal, entonces termina la ejecución del script. Si el archivo script actual fue nombrado por las opciones de configuración auto_prepend_file o auto_append_file en php.ini, entonces se termina la ejecución de ese archivo script.

Para más información, ver Retornando valores.

Nota: Cabe señalar que dado que return es un constructor del lenguaje y no una función, los paréntesis que rodean su argumentos no son necesarios. Es común no utilizarlos, y en realidad se debería hacer así a fin de que PHP tenga menos trabajo que hacer en este caso.

Nota: Si no se suministra un parámetro, entonces el paréntesis debe omitirse y NULL será retornado. Llamadas a return con paréntesis pero sin argumentos resultarán en un error del intérprete.

Nota: Nunca se deben usar paréntesis al rededor de la variable de retorno cuando se retorna por referencia, ya que esto no funcionará. Sólo se pueden retornar variables por referencia, no el resultado de una sentencia. Si se utiliza return ($a); entonces no se está retornando una variable, sino el resultado de la expresión ($a) (el cual es, por supuesto, el valor de $a).

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User Contributed Notes 4 notes

up
3
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
1
Tom
2 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
0
J.D. Grimes
9 months 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
-2
andrew at neonsurge dot com
5 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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