Re: Pass by reference (5.1.1 vs 5.1.2)

It looks like http://www.php.net/manual/en/language.operators.assignment.php could use a bit of updating. A paragraph about php 5 or a link to the semantics changes for php 5 would help newbies. The text about php4 says there is copy on assignment, which implies a performance hit for using = instead of =&, but I believe "copy on change" is more accurate. It wouldn't hurt to explicitly say that "=" is generally better than "=&" (unless you really need an alias). A user comment has been there unchallenged for over 2 years saying you can pass an assignment as a reference to a function, so it isn't surprising that someone considered the 5.1.1 to 5.1.2 change an issue. (Not that a user comment should bind the php devs, but when the comment goes unchallenged, it can lead to false impressions.) Perhaps some text explaining the assignment returns an r-value would be helpful. (If people understand "($x = 1) = 2;" shouldn't work, they might understand that passing "$x=1" to a function by reference shouldn't affect $x. (or should "($x = 1) = 2;" work and 5.1.2 had a real bug?)) I have to say the documentation for php is completely awesome and is a major factor in our company using the language. I just point out the above to help; it isn't a complaint. BTW, I disagree with the post below that indicates the issue is the order of calling. There is no way to call a function before doing the work in the argument list. If I call f(1+2), I can be sure the computation to get 3 will be performed _before_ calling f. The issue with f($p=array()) is that "$p=array()" is an r-value. - Todd On Mon, 2006-07-24 at 19:16 +0200, Johannes Schlueter wrote: > Hi, > > On Monday 24 July 2006 17:52, Rishad Omar wrote: > > getArray($p = array()); > > Here you are relying on undefined behavior. It is not defined wether $p = > array() or the function call getarray($p) should be executed first so the > order might always change. > > You should always use the two lines > $p = array(); > getArray($p); > to be safe. > > johannes > -- Todd Ruth <truth@proposaltech.com>