References / Pointers in PHP

[bcarl314]

I've got some code which reads in large amounts of data from a database into an array and passes the data between a few functions to display the information I need.

I know in PERL I can use references to save on memory usage when passing arrays, and since PHP has roots in PERL I'm guessing there's a way to do it. A quick search hasn't given me any results, (unless I'm using the wrong terms).

Does anybody use references / pointers in PHP? If so can you point (no pun intended) me to a reference (ok, pun intended )?

Thanks

[mordred]

There is quite an extensive manual section on the usage of references, at least how the PHP developers thought they should be applied:

http://us2.php.net/manual/en/language.references.php

I think you can use the ampersand in front of an array variable to create a reference to it.

$foo = array("bla", "barf", "bork");
$foo2 =& $foo; 

But try it out first, references in PHP are tricky.

[bcarl314]

Ok, I don't get the PHP references.

In PERL, if I reference a variable like this...

#!/usr/bin/perl
$var1 = "Hello";
$var2 = \$var1;
print $var2;

It prints out a memory location. In PHP if I use...

<?php
$a = "HELLO WORLD";
$b = & $a;
print "A:$a -- B:$b";
?>

All it does is print out the value of the variable.

Is there a way to pass the memory location and work with that in PHP???

[Celtboy]

nope. at leas, not that I'm aware of. You're seriously talking about using pointers here...don't think there's a way to get an actual memory address...

[Soy MrMike]

yeah just to reenforce what's already been said, I've come to PHP from a c++ background, and I haven't been able to use pointers.

However, part of the advantage that they provide in C++ is still provided in PHP. You can still do inexpensive assignments by assigning by reference, as in the example above. So if its inexpensive assignments you're after, you have it. I believe you can even return-by-reference.

However, if you're seeking superior control over memory, I'm not sure you can't get it... But that's the don't-worry-about-the-details-we'll-do-it-for-you nature of PHP.

[firepages]

do you/why do you , want the physical address ? , if you want to play with shared memory for application scope stuff then perhaps take a peek at the shmop functions ( also mmcache provides some shared memory operations) , else be happy that PHP works the way it does