Re: how to pass arguments by reference
Re: how to pass arguments by reference
- Subject: Re: how to pass arguments by reference
- From: James Montgomerie <email@hidden>
- Date: Wed, 10 Dec 2008 16:03:53 +0000
What you're looking to do is a C++ism, it's not available in Objective-
C; there's no explicit support for pass by reference.
It's certainly possible to achieve the same ends though. For
primitive types, you'll have to pass a pointer. Declare the method as
taking, for example 'int *' if you want to pass a pointer-to-int, and
call it by taking the address of the thing you want to pass a pointer
to (e.g. use '&myInt' if 'myint' is the primitive you want to pass by
reference).
For Obj-C objects, 'pass by reference' effectively always happens,
because you have to pass a pointer to the object (like an
'NSMutableString *') anyway.
Jamie.
On 10 Dec 2008, at 15:53, Nick Rogers wrote:
Hi, thanks for the reply.
Now I have:
- (UInt32)traverseTreeStraightReturnedDirection:(&int)treeDirection
returnedTreeDepth:(&int)treeDepth
returnedKey:(&HPlusCatalogKey)catKey
lookForKey:(HPlusCatalogKey)lastKey
{
// code here
}
Still the same error: parse error before & token
Thanks,
Nick
On 10-Dec-08, at 9:15 PM, Dave DeLong wrote:
Put the & before the variable type:
- (UInt32) traverseTreeStraightReturnedDirection:
(&int)treeDirection...
HTH,
Dave
On Dec 10, 2008, at 8:43 AM, Nick Rogers wrote:
Hi,
I have the following in my .m file:
- (UInt32)traverseTreeStraightReturnedDirection:(int&)treeDirection
returnedTreeDepth:(int&)treeDepth
returnedKey:(HPlusCatalogKey&)catKey
lookForKey:(HPlusCatalogKey)lastKey
{
// code here
}
But the error when compiling is "parse error before & token".
Is passing by reference not allowed or is there any other syntax
that I should follow?
Thanks,
Nick
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