PHP: return vs exit

[johnnnn]

In the manual, if return; is called globally, it immediately end script execution. To my knowlege, exit() and die() will do this too. Is there any difference in return vs exit()?

Thanks!

[Fou-Lu]

This is a good question actually, and I can't do a thing to test this (and definitely have never tried in the past :P).
I believe the only difference between the two is in regards to their usage within registered shutdown functions scope. I'm pretty certain that if you have say 3 functions registered at shutdown that calling return in the first on the stack still executes the remaining functions; however, calling die/exit terminates and the remaining two functions do not execute.
From the main() itself, then no, I believe they function exactly the same. I'm fairly certain that the return on main still triggers shutdown events (it seems illogical if it does not), and would return a status code of 0 (if left null with return;), or !0 if not null to correspond to common return results.
This may be one worth a test.

[MattF]

http://uk3.php.net/manual/en/function.return.php#83663

[Phil Jackson]

PHP Code:

<?php

function time_script_start(){
    $mtime = microtime();
       $mtime = explode(" ",$mtime);
       $mtime = $mtime[1] + $mtime[0];
       return $mtime;     
}
function time_script_end($starttime){
    $mtime = microtime();
       $mtime = explode(" ",$mtime);
       $mtime = $mtime[1] + $mtime[0];
       $endtime = $mtime;
       return ($endtime - $starttime);     
}

function test1($str){
    if($str===true){
        return true;    
    }else{
        exit(true);        
    }
}

PHP Code:

$st = time_script_start();
test1(true);
echo "<p>runtime: " . time_script_end($st) . "</p>"; 


runtime: 2.8848648071289E-5

PHP Code:

$st = time_script_start();
test1(false);
echo "<p>runtime: " . time_script_end($st) . "</p>"; 


1

[Fou-Lu]

Don't return/exit against the test1 with a value:

PHP Code:

function test1($str){
    if($str===true){
        return;    
    }else{
        exit;        
    }
} 


Also, I was sort of indicating shutdown registration:

PHP Code:

function time_script_start(){
    return microtime(true);   
}
function time_script_end($starttime){
    $mtime = microtime(true);
    printf("End time: %0.5f\n", ($mtime - $starttime));     
}

function test1($str){
    if($str===true){
        return;    
    }else{
        exit;        
    }
} 

$useReturn = true;
$start = time_script_start();
// Two tests, one with true, one with false.
register_shutdown_function('test1', $useReturn);
register_shutdown_function('time_script_end', $start);

printf("Start: %0.5f\n", $start);

?> 


Try that swapping that $useReturn true and false. I'd expect that the return against a standard function call versus the exit would differ since the return will push back up the stack, but I'm really curious if the same is true with the shutdown_functions.
If it works as expected (and I believe the return will continue), testing with 'true' should output:
Start: somefloat
End time: somefloat

And with false:
Start: somefloat

Can you test that one out?

Edit:
Oh oh, and also, once done can you also add a return; before the ?> but after the register_shutdown_function? I want to be certain that the return in main() still triggers shutdown events (I assumed it would).

[Phil Jackson]

PHP Code:

<?php

function time_script_start(){ 
    return microtime(true);    
} 
function time_script_end($starttime){ 
    $mtime = microtime(true); 
    printf("End time: %0.5f\n", ($mtime - $starttime));      
} 

function test1($str){ 
    if($str===true){ 
        return;     
    }else{ 
        exit;         
    } 
}  

$useReturn = true; 
$start = time_script_start(); 
// Two tests, one with true, one with false. 
register_shutdown_function('test1', $useReturn); 
register_shutdown_function('time_script_end', $start); 

printf("Start: %0.5f<br />\n", $start); 

?>

true:

Start: 1272910410.66400
End time: 0.00024

false:

Start: 1272910462.19000

[Fou-Lu]

Originally Posted by Phil Jackson

PHP Code:

<?php

function time_script_start(){ 
    return microtime(true);    
} 
function time_script_end($starttime){ 
    $mtime = microtime(true); 
    printf("End time: %0.5f\n", ($mtime - $starttime));      
} 

function test1($str){ 
    if($str===true){ 
        return;     
    }else{ 
        exit;         
    } 
}  

$useReturn = true; 
$start = time_script_start(); 
// Two tests, one with true, one with false. 
register_shutdown_function('test1', $useReturn); 
register_shutdown_function('time_script_end', $start); 

printf("Start: %0.5f<br />\n", $start); 

?>

true:

Start: 1272910410.66400
End time: 0.00024

false:

Start: 1272910462.19000

Great thats perfect. So return still follows it standard convention when using a stack scope.
Did you have a chance to test it by adding return; in the main()?

PHP Code:

<?php

function time_script_start(){ 
    return microtime(true);    
} 
function time_script_end($starttime){ 
    $mtime = microtime(true); 
    printf("End time: %0.5f\n", ($mtime - $starttime));      
} 

function test1($str){ 
    if($str===true){ 
        return;     
    }else{ 
        exit;         
    } 
}  

$useReturn = true; 
$start = time_script_start(); 
// Two tests, one with true, one with false. 
register_shutdown_function('test1', $useReturn); 
register_shutdown_function('time_script_end', $start); 

printf("Start: %0.5f<br />\n", $start); 
return;
?>

Just with $useReturn true, I'm curious if that still triggers shutdown events (I really hope it does >.<).

[Phil Jackson]

Sorry, Fou-lu, watching snooker!

PHP Code:

<?php


function time_script_start(){  
    return microtime(true);     
}  
function time_script_end($starttime){  
    $mtime = microtime(true);  
    printf("End time: %0.5f\n", ($mtime - $starttime));       
}  

function test1($str){  
    if($str===true){  
        return;      
    }else{  
        exit;          
    }  
}   

$useReturn = true;  
$start = time_script_start();  
// Two tests, one with true, one with false.  
register_shutdown_function('test1', $useReturn);  
register_shutdown_function('time_script_end', $start);  

printf("Start: %0.5f<br />\n", $start);  
return; 

?>

True:

Start: 1272920406.01300
End time: 0.00011

False:

Start: 1272920475.35800

[Fou-Lu]

Sweet, thanks for testing mate.
So yeah, in a main() scope the return is identical to exit in every way.

[kbluhm]

If you `return` in a nested file, it will halt the execution of that file only, but still continue on into the parent file.

You can optionally return a value from an included file:

whatever.php

PHP Code:

<?php

return 'kbluhm';

$name = 'not kbluhm';

index.php

PHP Code:

<?php

$name = include './whatever.php';

echo $name; // kbluhm

[Fou-Lu]

Yes thats right; best I know exit within an include does actually just kill the include much like the return, but I don't believe that its actually assignable. And those would both be considered main.
So a situation where its not the same. Interesting.

[kbluhm]

Originally Posted by Fou-Lu

Yes thats right; best I know exit within an include does actually just kill the include much like the return, but I don't believe that its actually assignable. And those would both be considered main.
So a situation where its not the same. Interesting.

`exit` will halt everything. `return` just halts the file or function in which it was called.

[Fou-Lu]

Originally Posted by kbluhm

`exit` will halt everything. `return` just halts the file or function in which it was called.

I'm embarassed; I should have known better. What is the point to die if you cannot die? Lol.

[kbluhm]

Originally Posted by Fou-Lu

I'm embarassed; I should have known better. What is the point to die if you cannot die? Lol.

Haha... well `return` and die() are not the same. die() is simply an alias for exit(), so die() and exit() are identical in every way. If you die(), you die...

[Fou-Lu]

Originally Posted by kbluhm

If you die(), you die...

That looks like a new sig entry to me