Issue with autoreleasing NSMutableArray

I am unable to release NSMutableArray that I created in a method.

SqliteData *s = [SqliteData alloc];

items = [NSArray alloc];
items = [s getItems:parent];
[s release];

IN SQLITeDATA 开发者_如何转开发class

-(NSMutableArray *)getItems:(NSString *)parent
{
    NSMutableArray *items = [[[NSMutableArray alloc] init]autorelease];
    return items
}

The app crashes, if I remove the autorelease it works fine.

The correct version is :

SqliteData *s = [[SqliteData alloc] init];
items = [[s getItems:parent] retain];
[s release];

Which is similar, but less optimized, to :

SqliteData *s = [[[SqliteData alloc] init] autorelease];
items = [[s getItems:parent] retain];

Beware about memory leaks :

SqliteData *s = [SqliteData alloc];
items = [NSArray alloc]; // memory leak there!
items = [s getItems:parent];
[s release];

You are leaking memory, since your replace newly allocated items address with another.

And alloc without init is a non-sense. (you are allocating memory, but not initialized it!)

• You're overwriting first items with a different value on next line. You don't need that alloc first — it does nothing.

• It's invalid to use alloc without init. Use [[foo alloc] init] or [foo new].

• Autoreleased objects are only temporary (until end of life of current pool, which is usually life of thread or callback — don't expect object will survive much longer than duration of function it's in). You need to retain them.