Passing optional parameter by reference

[flameche]

How do I pass an optional parameter by reference?

when I do

function( $data = null ) works fine
but
function( & $data = null ) gives a parse error

[merkinmuffley]

i think you have to pick one: either you declare the function parameter to be passed by reference, or you give it a default, but it appears to me that you can't do both (i just tried it). so if the parameter must be declared with a default value, then you have to put the reference notation in each time you call the function. bummer.

[PyroX]

Why are you wanting to pass an optional parameter by reference?

[flameche]

Let say we have a function that optionally receives an object as a parameter and we want to avoid making a copy ( even if php uses shalow copy ) and prevent the user from having to provide the parameter if they don't want to pass one.

[PyroX]

I see, just checking thanks 🙂