Overview
We are all at starting phase of learning, PHP has a BIG question on what is the difference between die() and exit(). The excitement of preparing a code with both statements, searching for answers and getting to a result is heart whelming.
It’s a general tendency to use exit() for testing/stopping execution and die() for checking database connection/operations.
Let’s compare it both… A step by step explanation to die Vs exit
PHP Language Constructs comparison “exit” Vs “die”:
NOTE: Built-in Functions are slower compared to Language Constructs, Language Constructs does not need parenthesis
Example 1:
Test exit:
<?php
for($count=0;$count<10;$count++) {
if($count==2)
exit(); // stops execution from this.
}
?>
Test die:
<?php
for($count=0;$count<10;$count++) {
if($count==2)
die(); // stops execution from this - (same as above)
}
?>
Example 2:
Test exit:
<?php
$dblink = mysql_connect('host.domain.com', 'mysql_user_one', 'mysql_password_for_user_one');
if (!$link) {
exit('Could not connect: ' . mysql_error()); // stops execution printing "Could not connect: MYSQL_ERROR"
}
echo 'Connected successfully';
mysql_close($link);
?>
Test die:
<?php
$dblink = mysql_connect('host.domain.com', 'mysql_user_one', 'mysql_password_for_user_one');
if (!$link) {
die('Could not connect: ' . mysql_error()); // stops execution printing "Could not connect: MYSQL_ERROR" - (same as above)
}
echo 'Connected successfully';
mysql_close($link);
?>As mysql_connect is deprecated from PHP 5.5 and is obsolete on PHP 7 you can try with mysqli_connect. Both (exit and die) can be used without parenthesis.
Example 3:
Test exit:
<?php
for($count=0;$count<10;$count++) {
if($count==2)
exit; // stops execution from this.
}
?>
Test die:
<?php
for($count=0;$count<10;$count++) {
if($count==2)
die; // stops execution from this - (same as above)
}
?>The conclusion comes that both works SAME – there is no functional level differences with both.
If you check on php.net for die and exit definitions it’s mentioned:
exit — Output a message and terminate the current script
die — Equivalent to exit
But still there is a little or no difference – server need to read 4 characters for exit whereas server need to read 3 characters for die. For micro time difference die will execute faster then exit.
These are called “Aliases” – different name but same functional execution.
There are many more function aliases – you can get a grip from http://php.net/manual/en/aliases.php.
I insist to use die instead of exit on regular basis. Ultimately it’s on developer to choose on what to use, there is lot more than “Hello World” to explore.