Memory Management in returning variables

[chuck]

I've been told that every time you allocate a variable, you have to release it. However, when I allocate a variable and then return it, there's no way to deallocate it. How do you release variables in this case or does the system auto-release them then?

(NSString *)sayHi:(NSString *)name {
  NSString *myName = [NSString alloc] initWithFormat:@"Hi, %@", name];
  
  // I can't release myName here, because then I wouldn't be able to return it.
  return myName;
}

Here's another example:

(NSString *)norrisizeMe:(NSString *)name {
  NSString *myName = [NSString alloc] initWithFormat:@"%@ Norris", name];

  // I can't release myName here, because I need it!
  return [NSString stringWithFormat:@"Hi, %@", myName;
}

[Kalimba]

Originally Posted by chuck

I've been told that every time you allocate a variable, you have to release it. However, when I allocate a variable and then return it, there's no way to deallocate it. How do you release variables in this case or does the system auto-release them then?

(NSString *)sayHi:(NSString *)name {
  NSString *myName = [NSString alloc] initWithFormat:@"Hi, %@", name];
  
  // I can't release myName here, because then I wouldn't be able to return it.
  return myName;
}

Here's another example:

(NSString *)norrisizeMe:(NSString *)name {
  NSString *myName = [NSString alloc] initWithFormat:@"%@ Norris", name];

  // I can't release myName here, because I need it!
  return [NSString stringWithFormat:@"Hi, %@", myName;
}

That's (one of the reasons) why Obj-C (NSObject, actually) provides an 'autorelease' mechanism.

[chuck]

Originally Posted by Kalimba

That's (one of the reasons) why Obj-C (NSObject, actually) provides an 'autorelease' mechanism.

So you're saying I just need to add:

[myName autorelease];

right before the return statement?

[Kalimba]

Originally Posted by chuck

So you're saying I just need to add:

[myName autorelease];

right before the return statement?

Yep. Or you use the abbreviated version, which combines the autorelease and return into one statement:

return [myName autorelease];