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Cannot create an NSPersistentStoreCoordinator with a nil model
... error: ` __persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel: [self managedObjectModel]];` Changing to mom doesn't seem to fix anything though
– Dominic Williams
Sep 9 '11 at 12:55
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Different between parseInt() and valueOf() in java?
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There is a difference - the new Object (potentially) allocated by valueOf comes with an overhead (memory for the object, handling, GC), while the plain int is extremely "lightweight". (For the most common values, you'll get references to pre-existing Objects, which helps a tiny...
How to implement the factory method pattern in C++ correctly
... something like Qt's shared classes to avoid copying overhead.
As for the allocation type, the main reason to use the factory pattern is usually polymorphism. Constructors can't be virtual, and even if they could, it wouldn't make much sense. When using static or stack allocation, you can't create ...
Why does struct alignment depend on whether a field type is primitive or user-defined?
...e conscious decision.
EDIT
The sizes are actually accurate only when allocated on a heap but the structs themselves have smaller sizes (the exact sizes of it's fields). Further analysis seam to suggest that this might be a bug in the CLR code, but needs to be backed up by evidence.
I will in...
Getting a list of files in a directory with a glob
...t all of the files in /bin.
You are responsible for cleaning up the memory allocated by glob by calling globfree when you're done with the structure.
In my example I use the default options and no error callback. The man page covers all of the options in case there's something in there you want t...
Changing every value in a hash in Ruby
...}%" }
Less code and clear intent. Also faster because no new objects are allocated beyond the values that must be changed.
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Long press gesture on UICollectionViewCell
...ILongPressGestureRecognizer *lpgr
= [[UILongPressGestureRecognizer alloc]
initWithTarget:self action:@selector(handleLongPress:)];
lpgr.delegate = self;
lpgr.delaysTouchesBegan = YES;
[self.collectionView addGestureRecognizer:lpgr];
}
-(void)handleLongPress:...
How to name factory like methods?
...t word I can think of off the top of my head is 'Construct'. In the past, 'Alloc' (allocate) might have been used in similar situations, reflecting the greater emphasis on blocks of data than objects in languages like C.
'Create' is a short, simple word that has a clear intuitive meaning. In most ca...
Storing custom objects in an NSMutableArray in NSUserDefaults
...ray];
if (oldSavedArray != nil)
objectArray = [[NSMutableArray alloc] initWithArray:oldSavedArray];
else
objectArray = [[NSMutableArray alloc] init];
}
You should check that the data returned from the user defaults is not nil, because I believe unarchiving from nil causes a...
Why is the shovel operator (
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This answer is based on a false premise: both allocating and freeing short-lived objects is essentially free in any halfway decent modern GC. It is at least as fast as stack allocation in C and significantly faster than malloc / free. Also, some more modern Ruby implemen...