Objective-C Language Memory Management Manual Memory Management
Example
This is an example of a program written with manual memory management. You really shouldn't write your code like this, unless for some reason you can't use ARC (like if you need to support 32-bit). The example avoids @property notation to illustrate how you used to have to write getters and setters.
@interface MyObject : NSObject {
NSString *_property;
}
@end
@implementation MyObject
@synthesize property = _property;
- (id)initWithProperty:(NSString *)property {
if (self = [super init]) {
// Grab a reference to property to make sure it doesn't go away.
// The reference is released in dealloc.
_property = [property retain];
}
return self;
}
- (NSString *)property {
return [[property retain] autorelease];
}
- (void)setProperty:(NSString *)property {
// Retain, then release. So setting it to the same value won't lose the reference.
[property retain];
[_property release];
_property = property;
}
- (void)dealloc {
[_property release];
[super dealloc]; // Don't forget!
}
@end
int main() {
// create object
// obj is a reference that we need to release
MyObject *obj = [[MyObject alloc] init];
// We have to release value because we created it.
NSString *value = [[NSString alloc] initWithString:@"value"];
[obj setProperty:value];
[value release];
// However, string constants never need to be released.
[obj setProperty:@"value"];
[obj release];
}
