declare
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.
return
Wird die return() Anweisung innerhalb einer Funktion aufgerufen, wird die Ausführung der Funktion sofort beendet und das Argument als Wert des Funktionsaufrufs zurückgegeben. return() beendet auch die Ausführung einer eval() Anweisung oder einer Skriptdatei.
Erfolgt der Aufruf innerhalb des globalen Bereichs, wird die Ausführung des aktuellen Skripts beendet. Wurde das aktuelle Skript include()ed oder require()ed, wird die Kontrolle an das aufrufende Skript zurückgegeben. Wurde das aktuelle Skript include()ed, wird der Wert, der return() zugewiesen wurde, als Wert des Aufrufs von include() zurückgegeben. Wird return() innerhalb des Hauptskripts aufgerufen, wird die Ausführung beendet. Handelt es sich bei dem Skript um eine Datei, die über die Einträge auto_prepend_file oder auto_append_file in der php.ini aufgerufen wurde, wird die Ausführung dieses Skripts beendet.
Weitere Informationen erhalten Sie im Abschnitt Rückgabewerte.
Hinweis: Beachten Sie, dass return() ein Sprachkonstrukt und keine Funktion ist. Die Klammern um ein Argument sind deshalb nur zwingend notwendig, wenn es sich um einen Ausdruck handelt, dessen Ergebnis zurückgegeben werden soll. Es ist gebräuchlich die Klammern wegzulassen, wenn eine Variable zurück gegeben soll.
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User Contributed Notesreturn
andrew at neonsurge dot com
15-Aug-2008 09:40
15-Aug-2008 09:40
stoic
06-Jun-2008 02:21
06-Jun-2008 02:21
Just to clear things up, if using return on a global scope it will end EXECUTION but NOT PROCESSING.
for example:
file a.php
<?php
if(defined("A")) return;
define("A", true);
echo "Hello";
?>
file b.php
<?php
include("a.php");
include("a.php");
?>
will output "Hello" only once.
but if file a.php is
<?php
if(defined("A")) return;
define("A", true);
function foo(){
}
?>
running file b.php will produce error:
Fatal Error: Cannot redeclare foo()...
Denis.Gorbachev
02-Dec-2007 10:06
02-Dec-2007 10:06
direct true 0.59850406646729
direct false 0.62642693519592
indirect true 0.75077891349792
indirect false 0.73496103286743
It is generally more true, because indirect method implies creating additional variable and assigning a value to it.
But, you know, "results may vary".
mr dot xanadu at gmail dot com
12-Oct-2007 09:56
12-Oct-2007 09:56
I was wondering what was quicker:
- return a boolean as soon I know it's value ('direct') or
- save the boolean in a variable and return it at the function's end.
<?php
$times = 50000;
function return_direct ($boolean)
{
if ($boolean == true)
{
return true;
}
return false;
}
function return_indirect ($boolean)
{
$return = false;
if ($boolean == true)
{
$return = true;
}
return $return;
}
/* Direct, return true */
$time_start = microtime(true);
for ($i = 1; $i <= $times; $i++)
{
return_direct(true);
}
$time_end = microtime(true);
$time_direct_true = $time_end - $time_start;
/* Direct, return false */
$time_start = microtime(true);
for ($i = 1; $i <= $times; $i++)
{
return_direct(false);
}
$time_end = microtime(true);
$time_direct_false = $time_end - $time_start;
/* Indirect, return true */
$time_start = microtime(true);
for ($i = 1; $i <= $times; $i++)
{
return_indirect(true);
}
$time_end = microtime(true);
$time_indirect_true = $time_end - $time_start;
/* Direct, return false */
$time_start = microtime(true);
for ($i = 1; $i <= $times; $i++)
{
return_indirect(false);
}
$time_end = microtime(true);
$time_indirect_false = $time_end - $time_start;
echo "<pre>";
echo "direct true\t" . $time_direct_true;
echo "\ndirect false\t" . $time_direct_false;
echo "\nindirect true\t" . $time_indirect_true;
echo "\nindirect false\t" . $time_indirect_false;
echo "<pre>";
?>
Representative results:
direct true 0.163973093033
direct false 0.1270840168
indirect true 0.0733940601349
indirect false 0.0742440223694
Conclusion: saving the result in a variable appears to be faster. (Please note that my test functions are very simple, maybe it's slower on longer functions)
Spacecat
25-Jul-2007 02:13
25-Jul-2007 02:13
regardez this code:
print pewt( "hello!" );
function pewt( $arg )
{
include( "some_code.inc" );
}
some_code.inc:
return strtoupper( $arg );
.. after much hair pulling, discovered why nothing was being returned by the "some_code.inc" code in the function .. the return simply returns the result TO the function (giving the include function a value), not to the CALLING (print pewt). This works:
print pewt( "hello!" );
function pewt( $arg )
{
return include( "some_code.inc" );
}
So, RETURN works relative to block it is executed within.
warhog at warhog dot net
18-Dec-2005 08:28
18-Dec-2005 08:28
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".