CODEWITHSUNDEEP
objective-ciosmemory-management
Eli
Eli

Reputation: 107

alloc and release problems

I can't figure out why my app is crashing after a few times I'm doing:

potionsT is nonatomic, retain, readonly.

-(void)First:(NSString*)Potions {

    potionsT = [[NSString alloc] initWithString:Potions];
}

-(void)After:(NSString*)Potions {
    [potionsT release];
    potionsT = [[NSString alloc] initWithString:Potions];

You see, I'm first calling First and after that I'm calling a few times After: and wopes, it crashes. with ECX_BAD_ACCESS.. I'm pretty noob with all that memory manage thing, I know that... Thanks!

Upvotes: 0

Views: 77

Answers (3)

Caleb
Caleb

Reputation: 125037

If you've set up potionsT as a property, you should access it that way:

-(void)first:(NSString*)potions {
    self.potionsT = potions;
}

-(void)after:(NSString*)potions {
    self.potionsT = potions;
}

In both cases, I changed your code to use the accessor for potionsT (that's what the self.potionsT means). I'm also not creating a new string, but just retaining the provided one. Since NSStrings are immutable, the result is the same. For best results, though, change the potionT property from retain to copy. That way, if a mutable string gets passed in, it'll be copied instead of retained (and immutable strings will still just be retained).

Upvotes: 2

Rudy Velthuis
Rudy Velthuis

Reputation: 28846

Did you @synthesize the property in the @implementation for the class? If so, then you should use:

self.potionsT = Potions;

if you use

potionsT = ...

then you are accessing the ivar, not the property. To access the property and let it do the memory management for you, you must precede it with an instance reference, and that can also be self.

If you use the property, you should not release potionsT manually, since the property already does that for you.

Upvotes: 2

Filip Radelic
Filip Radelic

Reputation: 26683

The point of retained property is it handles retain and release when you set it.

- (void)first:(NSString*)potions
{
    self.potionsT = potions; // will automatically release old value and retain new
}

- (void)after:(NSString*)potions
{
    self.potionsT = potions; // same as above
}

Also note how i renamed your Potions to potions, First: to first:, and After: to after:. Objective-C naming convention is to start variables and methods with lowercase letter, and class names with capital.

Upvotes: 3

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