PHP Velho Oeste 2024

goto

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

What's the worse thing that could happen if you use goto?
Image courtesy of » xkcd

The goto operator can be used to jump to another section in the program. The target point is specified by a case-sensitive label followed by a colon, and the instruction is given as goto followed by the desired target label. This is not a full unrestricted goto. The target label must be within the same file and context, meaning that you cannot jump out of a function or method, nor can you jump into one. You also cannot jump into any sort of loop or switch structure. You may jump out of these, and a common use is to use a goto in place of a multi-level break.

Example #1 goto example

<?php
goto a;
echo
'Foo';

a:
echo
'Bar';
?>

The above example will output:

Bar

Example #2 goto loop example

<?php
for($i=0,$j=50; $i<100; $i++) {
while(
$j--) {
if(
$j==17) goto end;
}
}
echo
"i = $i";
end:
echo
'j hit 17';
?>

The above example will output:

j hit 17

Example #3 This will not work

<?php
goto loop;
for(
$i=0,$j=50; $i<100; $i++) {
while(
$j--) {
loop:
}
}
echo
"$i = $i";
?>

The above example will output:

Fatal error: 'goto' into loop or switch statement is disallowed in
script on line 2

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User Contributed Notes 4 notes

up
44
Lollo
3 years ago
You should mention the label can't be a variable
up
20
devbyjesus at example dot com
2 years ago
the problem of goto is that it is a good feature but in a large codebase it reduces the readability of the code . that's all . i try to not use it to think about the person who is going to read after me .
up
8
BPI
1 year ago
You can jump inside the same switch. This can be usefull to jump to default
<?php
$x
=3;
switch(
$x){
    case
0:
    case
3:
        print(
$x);   
        if(
$x)
            goto
def;
    case
5:
       
$x=6;
    default:
       
def:
        print(
$x);
}
?>
up
3
Anonymous
7 months ago
Example to exit loops:

for ($i = 0; $i < 10; $i++) {
    for ($j = 0; $j < 10; $j++) {
        if ($condition) {
            goto exit;
        }
    }
}
exit:
echo "Out of the loop.";
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