Re: NSTimer and seg faults

FROM : Hank Heijink (Mailinglists)
DATE : Wed Mar 12 22:08:27 2008

You're getting an autoreleased date and autoreleased timer from the 
methods you call, but you're not retaining either your timer our your 
date, so they'll both be gone after you leave awakeFromNib.

Read the memory management guide for how all this works:

<http://developer.apple.com/documentation/Cocoa/Conceptual/MemoryMgmt/MemoryMgmt.html
>

In the meantime try

lastUpdate = [[NSDate alloc] init];

and put a retain around your scheduledTimer. Also, your updateTimer 
callback doesn't need an NSTimer * argument.

Good luck!
Hank

On Mar 12, 2008, at 4:56 PM, Gregory Short wrote:

>     Howdy all, first-time poster here. I'm pretty new to Objective-C 
> and it's associated run-time environment, so I apologize if this is 
> a total newbie question that has been answered before (I couldn't 
> find anything, but I might not know where to look.)
>     My problem is this: I have an NSTimer which I set up in my NSView's 
> -awakeFromNib method. Also in -awakeFromNib, I set create an NSDate 
> object as part of the NSView. This all works fine. The problem is, 
> when my timer fires, if I try to do anything at all with the NSDate 
> object I created before, the program chokes. Here's the relevant 
> portion of the code (I've stripped out what appears to be 
> irrelevant; if anyone wants to see more, that's fine.)
>
> BlobView.h:
>
> @interface BlobView : NSOpenGLView
> {
>     NSTimer* updateTimer;
>     NSDate* lastUpdate;
> }
>
> - (void) updateTimer: (NSTimer *) timer;
>
> @end
>
>
>
> BlobView.m:
>
> @implementation BlobView
>
> - (void) awakeFromNib {
>     lastUpdate = [NSDate date];
>     NSLog(@"%lf", [lastUpdate timeIntervalSinceNow]); // This works fine
>
>     updateTimer = [NSTimer scheduledTimerWithTimeInterval: 1.0 / 30.0
>         target: self
>         selector: @selector(updateTimer:)
>         userInfo: nil
>         repeats: YES];
> }
>
> - (void) updateTimer: (NSTimer *) timer {
>     NSLog(@"%lf", [lastUpdate timeIntervalSinceNow]); // This produces 
> a SIGBUS
> }
>
> @end
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