ECHO or PRINT which is faster? – You can see this kind of questions a lot in every PHP blog-space and most of the interview questions ;-). Most of us must be known the answer, Google it, you will ;-).

Yes you can say “ECHO” but how sure are you? We blindly believe on our experts, I agree I do a lot. But it feels something different when you see it on your naked eyes, don’t you? I do.

Recently while surfing (reading obviously) over the internet on various topics, I came across a nice tool which will exactly tell us WHO (language construct or pre-defined function) is GOOD in PHP.

VLD ( Vulcan Logic Dumper) – by Derrick Rethans, into the Zend Engine and dumps all the opcodes (execution units) of a script. It can be used to see what is going on in the Zend Engine.

After, trying this tool I was quite happy 🙂 and damn confident that ECHO is faster than PRINT. I will walk you through with the installation of this tool and a simple quick example.

Installing VLD….

The following operation are performed in Ubuntu Linux and please take
 care of the settings for other Linux machine.

1. Get the source from “svn co svn://svn.xdebug.org/svn/php/vld/trunk vld“.
2. “cd vld“
3. “phpize” – you can get this command only when you install PHP-Dev “aptitude install php5-dev“
4. “./configure“
5. “make install”

That’s it, you are done let’s try this thing.

Let’s TRY….

Use PHP’s command-line interface (CLI) to try this out.

Try executing the ECHO function:
$ php -d extension=vld.so -d vld.active=1 -d vld.execute=0 -r 'echo 1;'
[OR]
$ php -d extension=vld.so -d vld.active=1 -d vld.execute=0 -f file.php;
[OUTDATED - thanks to Rodrigo for waking me up]
$ php -d vld.active=1 -r 'echo 1;'

Finding entry points
Branch analysis from position: 0
Return found
filename: Command line code
function name: (null)
number of ops:  2
compiled vars:  none

line     #  op                           fetch          ext  return  operands
-------------------------------------------------------------------------------
   1     0  ECHO                                             ~0      1
         1  RETURN                                                   null

Now let's try executing the PRINT function:
$ php -d extension=vld.so -d vld.execute=0 -d vld.active=1 -r 'print 1;'

Finding entry points
Branch analysis from position: 0
Return found
filename: Command line code
function name: (null)
number of ops:  3
compiled vars:  none
line     #  op                           fetch          ext  return  operands
-------------------------------------------------------------------------------
   1     0  PRINT                                            ~0      'foo'
         1  FREE                                                     ~0
         2  RETURN

By looking at the “number of ops” value we can say that PRINT takes an extra 1 operation than ECHO to process. Now, try with your native code and see how Zend Engine process your file.

Happy Debugging!