Does copy allocate the required memory ?

Question

Hi,

Here is an example taken from Apple iPhone SDK project:

@interface EADSessionController : NSObject <EAAccessoryDelegate, NSStreamDelegate> {
    EAAccessory *_accessory;
    EASession *_session;
    NSString *_protocolString;

    NSMutableData *_writeData;
    NSMutableData *_readData;
}

...

// initialize the accessory with the protocolString
- (void)setupControllerForAccessory:(EAAccessory *)accessory withProtocolString:(NSString *)protocolString
{
    [_accessory release];
    _accessory = [accessory retain];
    [_protocolString release];
    _protocolString = [protocolString copy];
}

My understanding is that "copy" will also allocate the memory required to copy the protocolString object passed as an argument, and therefore there is not need to allocate (alloc) something before copying.

Am I right ?

Regards, Apple92

Answer 1

Correct. The copy starts out with a retain count of (at least) one, and you are responsible for eventually releasing it. (See Object Ownership Policy.)