On Mar 9, 2011, at 16:33, Jeffrey Walton wrote: > The > code executes properly on the first invocation, but crashes on the > second invocation. The cause of the crash is walker = [fileManager > enumeratorAtPath:directory].
You should post the error message and the backtrace at the time of the crash. "Crash" means different things in different contexts. > Any ideas on the cause? I experience the crash with both methods of > retrieving the file manager. Are there known issues with > enumeratorAtPath? No. Your symptoms, as far as they can be analyzed in the absence of specific information, sound like a memory management problem. The point at which the crash occurs is where the error was detected, not (necessarily) where the error really occurred. > directory = [NSHomeDirectory() > stringByAppendingPathComponent:@"Documents"]; > walker = [fileManager enumeratorAtPath:directory]; > while((file = [walker nextObject]) != nil) That's three objects you don't take ownership of after they're handed to you. I'd suggest starting by retaining them and releasing them before exiting from this piece of code. You can't assume they're autoreleased when handed to you (unless the documentation says so), and even then it's living dangerously to avoid retaining them when something allocation-heavy like directory enumeration is in progress. [This is not a garbage collected app, is it? If so, then the answer is different.] > According to 'NSFileManager Class Reference' > (http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSFileManager_Class/Reference/Reference.html): > > In iOS and Mac OS X v 10.5 and later you should consider > using [[NSFileManager alloc] init] rather than the singleton > method defaultManager. Instances of NSFileManager are > considered thread-safe when created using > [[NSFileManager alloc] init]. Some time back, an expert from Apple said that this documentation isn't exactly correct. IIRC, there is [no longer, at least] anything special about [NSFileManager defaultManager] -- except, I suppose, that it's a singleton, so should only be used by a single thread at one time. '[[NSFileManager alloc] init]' produces unique instances that should also be used by a single thread at one time. IOW, more or less, each thread should use its own NSFileManager instance. That's the only restriction. Also, IIRC, none of the individual instances is thread safe in the sense that it can be used by multiple threads at the same time. [The thread safety, I assume, comes from the ability to have multiple instances working at the same time, accessing a shared file system, which something quite different.] But I'm saying all this from imperfect memory, so I might have it wrong. _______________________________________________ Cocoa-dev mailing list ([email protected]) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [email protected]
