Question

i have function with return type as (NSArray/NSData/NSString/NSDictionary and so on). i can return and use as well ,but my problem arise @ release the object. Please guide me which one is best way to manage memory for returned object.if anything is wrong please ignore and give your best solution

i have refereed apple Memory management guide

A)

-(NSData *)somefunction2
{  
   NSData *data=[[[NSData alloc]init]autorelease];  
    // fill stuff for nsdata
   return data;
}

-(void)somefunction
{    
NSData *data=[self somefunction2];    
// use data    
}

but most of the blogs advice to avoid autorelease so i was using following type

B)

-(NSData *)somefunction2
{  
   NSData *data=[[NSData alloc]init];  
    // fill stuff for nsdata
   return data;
}

-(void)somefunction
{

NSData *data=[[self somefunction2] retain];

// use data

[data release];

}

C)

-(NSData *)somefunction2
{  
   NSData *data=[[[NSData alloc]init]autorelease];  
    // fill stuff for nsdata
   return data;
}

-(void)somefunction
{

NSData *data=[[self somefunction2] retain];

// use data

[data release];

}

Edit:
One more thing. if i try to pass Same allocted object to Some function call Argument or custom Delegate object ,Where i have to Release ????Whether below the function call or get retain in function def and then release.

NSData *data=[[NSData alloc]init];

[self somfunctioncall:data];

or

NSData *data=[[NSData alloc]init];

[delegate mydelegatefunction:data];


-(void)somfunctioncall:(NSdata *)data
{
NSData *newdata =[data retain];
//data use
[data release];}

Thanks in advance

Answer 1

The best practice is that if the method contains either alloc, init, new or retain, the method returns a retained object, and if it doesn’t it is returning an autoreleased object. I would suggest this:

-(NSString *)newData
{  
   NSData *data=[[NSData alloc]init];  
    // fill stuff for nsdata
   return data;
}

So that later you can just do this:

-(void)somefunction
{

NSData *data=[self newData];

// use data

[data release];

}