Apple

On Feb 21, 2011, at 3:19 PM, Tony Romano wrote:

<snip>

-(void) insert: (BTreeNode **) node node:(BTreeNode *) n
{
…

// get the address of the left member
[self insert:&[(*node) left] node:n]; // <--- error
}

The compiler(GCC 4.2 or LLVM 1.6) is giving this error : address _expression_ must be an lvalue or a function designator.

The syntax you want is simply this:

BTreeNode *leftNote = [(*node) left];

[self insert:&leftNode node:n];

The return value for [(*node) left] may be an lvalue, but the _expression_ isn't. I don't know of a syntax that will let you get the address you want in one _expression_. However, in the interest of readability, I would prefer the two-line solution regardless.

Best,

Hank

References:
	>ObjC question (From: Tony Romano <email@hidden>)