What are the differences in die() and exit() in PHP?

Question

What are the differences between die() and exit() functions in PHP?

I think both have the same functionality, but I doubt there is something different in both... what is it?

Solution 1

There's no difference - they are the same.

PHP Manual for exit:

Note: This language construct is equivalent to die().

PHP Manual for die:

This language construct is equivalent to exit().

Solution 2

DIFFERENCE IN ORIGIN

The difference between die() and exit() in PHP is their origin.

• exit() is from exit() in C.
• die() is from die in Perl.

---

FUNCTIONALLY EQUIVALENT

die() and exit() are equivalent functions.

PHP Manual

PHP Manual for die:

This language construct is equivalent to exit().

PHP Manual for exit:

Note: This language construct is equivalent to die().

PHP Manual for List of Function Aliases:

die is an alias for master function exit()

---

DIFFERENT IN OTHER LANGUAGES

die() and exit() are different in other languages but in PHP they are identical.

From Yet another PHP rant:

...As a C and Perl coder, I was ready to answer, "Why, exit() just bails off the program with a numeric exit status, while die() prints out the error message to stderr and exits with EXIT_FAILURE status." But then I remembered we're in messy-syntax-land of PHP.

In PHP, exit() and die() are identical.

The designers obviously thought "Hmm, let's borrow exit() from C. And Perl folks probably will like it if we take die() as is from Perl too. Oops! We have two exit functions now! Let's make it so that they both can take a string or integer as an argument and make them identical!"

The end result is that this didn't really make things any "easier", just more confusing. C and Perl coders will continue to use exit() to toss an integer exit value only, and die() to toss an error message and exit with a failure. Newbies and PHP-as-a-first-language people will probably wonder "umm, two exit functions, which one should I use?" The manual doesn't explain why there's exit() and die().

In general, PHP has a lot of weird redundancy like this - it tries to be friendly to people who come from different language backgrounds, but while doing so, it creates confusing redundancy.

Solution 3

As stated before, these two commands produce the same parser token.

BUT

There is a small difference, and that is how long it takes the parser to return the token.

I haven't studied the PHP parser, but if it's a long list of functions starting with "d", and a shorter list starting with "e", then there must be a time penalty looking up the function name for functions starting with "e". And there may be other differences due to how the whole function name is checked.

I doubt it will be measurable unless you have a "perfect" environment dedicated to parsing PHP, and a lot of requests with different parameters. But there must be a difference, after all, PHP is an interpreted language.

Solution 4

PHP manual on die:

die — Equivalent to exit

You can even do die; the same way as exit; - with or without parens.

The only advantage of choosing die() over exit(), might be the time you spare on typing an extra letter ;-)

Solution 5

Here is something that's pretty interesting. Although exit() and die() are equivalent, die() closes the connection. exit() doesn't close the connection.

die():

<?php
    header('HTTP/1.1 304 Not Modified');
    die();
?>

exit():

<?php
    header('HTTP/1.1 304 Not Modified');
    exit();
?>

---

Results:

die():

HTTP/1.1 304 Not Modified 
Connection: close

exit():

HTTP/1.1 304 Not Modified 
Connection: Keep-Alive 
Keep-Alive: timeout=5, max=100

Just incase in need to take this into account for your project.

Credits: https://stackoverflow.com/a/20932511/4357238

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