how to release an object which use copy keyword in iOS program

Question

In my program, I tried to set object in an dictionary. Values are coming from another class, so I copied those values before processing it.

While analyzing the code I got leaks.

-(void)giveInput:(NSString *)userInput ForPlaceholder:(NSString *)placeholder{

    [inputValue setObject:[userInput copy] forKey:[placeholder copy]];

}

How to release the userINput and Placehoder object retain count?

Answer 1

According to the Memory Management Programming Guide, you should release or at least autorelease any references you got from alloc, new or copy.

In your case, try changing [userInput copy] to [[userInput copy] autorelease]; likewise for placeholder.

EDIT: Note though, the default NSDictionary and NSMutableDictionary classes already copy keys and retain values -- see the Memory Management Programming Guide as well as the NSMutableDictionary class reference for further details. Hence, there's no need for [placeholder copy], and if you did not mean to create a separate copy of userInput, there is no need to copy it also.

Answer 2

-(void)giveInput:(NSString *)userInput ForPlaceholder:(NSString *)placeholder{
    NSString *cpUserInput = [userInput copy];
    NSString *cpPlaceholder = [placeholder copy];
    [inputValue setObject:cpUserInput forKey:cpPlaceholder];
    [cpUserInput release];
    [cpPlaceholder release];
}

Or in a fewer lines with autorelease:

[inputValue setObject:[[userInput copy] autorelease] forKey:[[placeholder copy] autorelease]];

*when adding objects to dictionaries/arrays they get retained