Why memory consumption grows? - objective-c

Question

Here is a very simple piece of code:
- (void)functionOne
{
[self performSelector:#selector(functionTwo) withObject:nil afterDelay:1.0];
}
- (void)functionTwo
{
[self performSelector:#selector(functionOne) withObject:nil afterDelay:1.0];
}
As you can see there's nothing in these two methods what could cause growth of memory consumption. But it grows. Very slowly, but it does. About 0.01 MB every three seconds. Why? How can i avoid it?

Answer 1

You are effectively creating an infinite loop. If you want to switch the state of an object every one second (as you said in the comments), do it this way:
Create a method like so:
- (void)functionOne
{
if( [obj isEqual:stateA] ) {
obj = stateB;
} else {
obj = stateA;
}
}
and call it with a timer:
NSTimer* myTimer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self
selector:#selector(functionOne) userInfo:nil repeats:YES];

Answer 2

to avoid infinite loops you should use a NSTimer and one function, in which you toggle the state of your object.
in your init method, or something like viewDidLoad you should start a timer like
- (void)viewDidLoad {
[super viewDidLoad];
[NSTimer scheduledTimerWithTimeInterval:1.0
target:self
selector:#selector(switchState:)
userInfo:nil
repeats:YES];
}
then you use one method like
- (void) switchState:(NSTimer *)timer {
if ([[self yourState] isEqual:stateOne]) {
[self setYourState:stateTwo];
} else {
[self setYourState:stateOne];
}
}
for more information see http://developer.apple.com/library/ios/#documentation/cocoa/reference/Foundation/Classes/NSTimer_Class/Reference/NSTimer.html

Answer 3

The memory grows simply because the Application needs to hold onto some state. Each time you call perform selector that selector is pushed onto the stack. This stack is saved in memory. Hence the growth.