(PHP 4, PHP 5, PHP 7)
return returns program control to the calling module. Execution resumes at the expression following the called module's invocation.
If called from within a function, the return statement immediately ends execution of the current function, and returns its argument as the value of the function call. return also ends the execution of an eval() statement or script file.
If called from the global scope, then execution of the current script file is ended. If the current script file was included or required, then control is passed back to the calling file. Furthermore, if the current script file was included, then the value given to return will be returned as the value of the include call. If return is called from within the main script file, then script execution ends. If the current script file was named by the auto_prepend_file or auto_append_file configuration options in php.ini, then that script file's execution is ended.
For more information, see Returning values.
Note: Note that since return is a language construct and not a function, the parentheses surrounding its arguments are not required. It is common to leave them out, and you actually should do so as PHP has less work to do in this case.
Note: If no parameter is supplied, then the parentheses must be omitted and
NULLwill be returned. Calling return with parentheses but with no arguments will result in a parse error.
Note: You should never use parentheses around your return variable when returning by reference, as this will not work. You can only return variables by reference, not the result of a statement. If you use return ($a); then you're not returning a variable, but the result of the expression ($a) (which is, of course, the value of $a).
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".
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!
I wonder if return in the global scope would be a semantic way to store low-level, pure-PHP config arrays while avoiding polluting the global scope. For example:
<?php
// app.php
function app() {
$conf = include('conf.php');
}
app();
<?php
// conf.php
return [
'db' => [
'host' => '127.0.0.1',
'username' => 'user',
'password' => 'pass'
],
];
?>
This approach produces exactly 0 global variables.
(PS. I also tried this using a JS-like module pattern using an anonymous function but it seems that an anon function can't be defined and called in the same expression.)
Note that because PHP processes the file before running it, any functions defined in an included file will still be available, even if the file is not executed.
Example:
a.php
<?php
include 'b.php';
foo();
?>
b.php
<?php
return;
function foo() {
echo 'foo';
}
?>
Executing a.php will output "foo".
Following up on Tom and warhog's comments regarding using return in global scope, here is another reason not to do it:
For command line scripts, the return statement will NOT return a status to the OS!
<?php
if ($somethingBad)
return 42; // This will not work! You'll get 0 back instead!
else
return 0;
?>
Instead, you must use exit(): http://php.net/exit
<?php
if ($somethingBad)
exit(42); // OS will receive (int) 42 as the return code
else // everything is fine
exit(0);
?>
Also note, what you cannot do anything after the 'return' usage in function.
For example:
<?php
$_SESSION['text'] = 'Best PHP';
function getText()
{
$text = $_SESSION['text'];
return $text;
unset($_SESSION['text']);
}
echo getText().'<br />';
echo $_SESSION['text'];
?>
This will output:
Best PHP
Best PHP
Twice, because we have used unset() function after 'return'.
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.
