does the condition after && always get evaluated

Question

I have this if statement that tests for the 2 conditions below. The second one is a function goodToGo() so I want to call it unless the first condition is already true

$value = 2239;  if ($value < 2000 && goodToGo($value)){    //do stuff }  function goodToGo($value){    $ret = //some processing of the value    return $ret;  } 

My question is about the 2 if conditions $value < 2000 && goodToGo($value). Do they both get evaluated or does the second one only get evaluated when the first one is true?

In other words, are the following 2 blocks the same?

if($value < 2000 && goodToGo($value)) {    //stuff to do }  if($value < 2000) {     if (goodToGo($value)){        //stuff to do     } } 

Answer 1

No--the second condition won't always be executed (which makes your examples equivalent).

PHP's &&, ||, and, and or operators are implemented as "short-circuit" operators. As soon as a condition is found that forces the result for the overall conditional, evaluation of subsequent conditions stops.

From http://www.php.net/manual/en/language.operators.logical.php

// -------------------- // foo() will never get called as those operators are short-circuit  $a = (false && foo()); $b = (true  || foo()); $c = (false and foo()); $d = (true  or  foo()); 

Answer 2

Yes. The two blocks are the same. PHP, like most (but not all) languages, uses short-circuit evaluation for && and ||.