I'm new to NSZombie but I have a problem with my app crashing with EXC_BAD_ACCESS. I'm having real trouble finding the object that is causing the problem. Looking online I followed instructions to enable zombie objects.
The problem I'm having has been reported by another person on that page. Enabling zombie objects stops the bad access error but gives me no information. Nothing is printed by NSLog. Is there somewhere else I should look, or am I doing something wrong? I don't really know my way round XCode or a Mac very well as I'm mainly a C# programmer.
Any help would be most welcome.
1) Run your app on Intruments.
2) In instruments, select Object allocations tool(automatically selected if you select leaks tool).
3)Click on the little "i" on top left, within the Allocations tool.
4) Select "Enable NSZombie detection".
5) Press the record button and let your app run.
6) Go through the execution of the app untill it crashes. As soon as there is a crash, you'd see a pop up saying that there was a EXC_BAD_ACCESS. Click on the little -> on the pop up to see the object that has turned into a zombie and the line of code responsible.
Sorry I am unable to upload a screenshot, as am at work.
Expand your project Executable and right click on it. and click on GetInfo->Argument tag aat end of the window you see plus and minus sign button click on + sighn button and write
Name Value
NSZombieEnabled YES
then after execute your project and whenever crash your application click on run munu-> console you see there why your application crash. please try this may be this will help you.
Related
I searched StackOverflow and it doesn't look like many people are having this problem, but for me, this happens very, very frequently. Maybe not every time, but perhaps every other time.
Once I try to build and run the app, Xcode crashes, and in a strange way: it just disappears with no error messages, no suggestion to report the problem, nothing at all. This happened with Xcode 6.0 as well. It doesn't matter whether I am running the app on a device or on an emulator.
To prevent the crash, I need to Product > Clean. If I do this clean each time before running the app, crashes do not happen, but once I forget to do that, Xcode can crash any moment.
I don't think I ever had this crash with an old project, but it keeps happening with the project that I started in Xcode 6.0.
Because of that, iOS development is becoming for me quite a painful exercise, similar to pre-Android-Studio Android development.
Is it just my problem, or maybe someone else is having it? Maybe someone has a solution?
I just started running into the same issue and found a workaround for it. Found it to be an issue with building when Xcode is full screen. Seems silly, but so far exiting full screen mode has worked for me. I've been able to re-introduce the issue after building full screen a few times, and then instantly fix it again by exiting full screen.
Yeah, it's not that the app is crashing, it's just that the click is triggering the red close window button behind the red button (yeah, seriously). You'll notice, Xcode is still open, it's just that the window has closed. You might also notice that sometimes when you click "stop" in full screen mode, it switches to non full screen. Again, the tap is passing through the run/stop buttons to the underlying window controls.
So dumb.
I solved it using 'cmd + R' instead of clicking the run button
I am following the Stanford University iOS development course on iTunes U.
In one of the demos (that I have been trying to follow), there is this code that loads the property list from an NSURL and returns it as NSMutableDictionary.
-(NSMutableDictionary *) words
{
NSURL *wordsURL=[NSURL URLWithString:#"http://cs193p.stanford.edu/vocabwords.txt"];
words=[[NSMutableDictionary dictionaryWithContentsOfURL:wordsURL] retain];
return words;
}
The application is successfully built, but at runtime it gives the following error and gets stuck:
I can't figure out what the problem is. Can you please help?
You're stopped at a breakpoint. That's a debugging tool, not an error. See the blue arrow/tab in the left margin, where the line numbers are? Drag that away and drop it anywhere (you'll see a "poof") to remove it, then run your project again.
You can also deactivate all breakpoints by typing ⌘-Y, the key equivalent for the menu item Debug>Deactivate Breakpoints, or you can view all your breakpoints in the Breakpoint Navigator (hit ⌘-6).
When execution stops like this, you can continue from the breakpoint, either by typing continue at the debugger prompt in the Console:
(lldb) continue
Or hitting the "Play" button in the debugger controls. You can also type Control-⌘-Y, which is the equivalent for the menu item Debug>Continue.
This isn't an error. You just set a breakpoint (probably without knowing it).
Drag the little blue Chevron in the column at the left out of the way. You will see it disappear and go poof, and then you can rebuild your app and you should see it run properly.
Now, that said, I think there are some memory management mistakes in your code, but we can return to those later. ;-)
The program is stopping because you have a breakpoint.. That's the blue arrow on the left of the code. Right-click it and delete.
I am following the Stanford University iOS development course on iTunes U.
In one of the demos (that I have been trying to follow), there is this code that loads the property list from an NSURL and returns it as NSMutableDictionary.
-(NSMutableDictionary *) words
{
NSURL *wordsURL=[NSURL URLWithString:#"http://cs193p.stanford.edu/vocabwords.txt"];
words=[[NSMutableDictionary dictionaryWithContentsOfURL:wordsURL] retain];
return words;
}
The application is successfully built, but at runtime it gives the following error and gets stuck:
I can't figure out what the problem is. Can you please help?
You're stopped at a breakpoint. That's a debugging tool, not an error. See the blue arrow/tab in the left margin, where the line numbers are? Drag that away and drop it anywhere (you'll see a "poof") to remove it, then run your project again.
You can also deactivate all breakpoints by typing ⌘-Y, the key equivalent for the menu item Debug>Deactivate Breakpoints, or you can view all your breakpoints in the Breakpoint Navigator (hit ⌘-6).
When execution stops like this, you can continue from the breakpoint, either by typing continue at the debugger prompt in the Console:
(lldb) continue
Or hitting the "Play" button in the debugger controls. You can also type Control-⌘-Y, which is the equivalent for the menu item Debug>Continue.
This isn't an error. You just set a breakpoint (probably without knowing it).
Drag the little blue Chevron in the column at the left out of the way. You will see it disappear and go poof, and then you can rebuild your app and you should see it run properly.
Now, that said, I think there are some memory management mistakes in your code, but we can return to those later. ;-)
The program is stopping because you have a breakpoint.. That's the blue arrow on the left of the code. Right-click it and delete.
i m parsing a json in table view.clicking the tableview navigates to nextview.after few clicks the app gets crashed.I have set NSZombieEnabled in my environmental variable and i got this message in my console*** -[NSCFString isEqual:]: message sent to deallocated instance 0x1f31d0
how to trace back which variable exactly i m getting the leak would be great if you guys could help me out.
Did you try enabling the exception breakpoint? You can try tracking that zombie on instruments, the long way:
Run your app on Intruments.
In instruments, select Object allocations tool(automatically selected if you select leaks tool).
Click on the little "i" on top left, within the Allocations tool.
Select "Enable NSZombie detection".
Press the record button and let your app run.
Go through the execution of the app untill it crashes. As soon as there is a crash, you'd see a pop up saying that there was a EXC_BAD_ACCESS. Click on the little -> on the pop up to see the object that has turned into a zombie and the line of code responsible.
I'm writing a simple Cocoa Application, no core data or multiple document support. Running on a Mac Pro, OS X 10.6.6, Xcode 3.2.3.
I have reduced my application to the following code in my AppDelegate class:
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
NSOpenPanel *openPanel = [NSOpenPanel openPanel];
[openPanel runModal];
return;
}
From within the debugger, I will run my application. As expected a somewhat not-to-useful OpenPanel will appear. I will click Cancel and it will disappear. All this is as expected. When I click [Command + Q] to Quit the application, the UI will go away but the debugger will indicate that the application is still running (as does the console output).
Based upon all the information I'm reading, I should not have to do anything else in order for this to run right. I've downloaded several examples on the Open Panel's usage but most use the deprecated methods of opening modal giving additional information as parameters. FWIW, I tried those methods and am still seeing the same result.
One last item, when the Open dialog appears, just for an instant I see a message box asking me something to the extent if I want my application to receive incoming connections. The dialog quickly disappears. I don't know if that is part of my problem or not. [Update - this deals with my Firewall being turned on.]
Yes, I'm fairly new at Objective C but not at programming in general. Any words of wisdom is greatly appreciated!
2011.02.07 - Update:
I have walked the debugger line by line without incident. There is no indication of any program failure in the console window.
I say that the debugger is still active after [Command + Q] because the Stop Process toolbar button is still enabled as is the Break button. Further the console indicates that after I tell the application to terminate (either via the menu or key command) that it is still running. The following is the Complete console output from start of run to after I Quit the application.
Program loaded.
run
[Switching to process 62370]
Running...
The Activity Monitor (system tool) will show my application terminating (no longer shows up as a process) but the Debugger will still not transition to "edit" mode - if I tell Xcode to run the debugger again, it will ask me if it's OK to Stop the current debugging session. If I was in Windows I would start looking for background threads keeping the process alive but as far as I know, NSOpenPanel should not be doing something like that.
I have further simplified the program to nothing more than creating a brand new Cocoa application and inserting the code snippet above - no other additions to the template project or updates in any way.
And lastly, when the application is run under the Leaks Performance Tool, everything runs fine when the panel is created but never used. When created and actually used though, at the end of the run I will get the following message in the tool "insufficient task_for_pid privileges (leakagent64)". Googling this hurts. If I read it right, the debugger does not have sufficient permissions to fully kill the target process ??? Now that sounds stupid but ... It does not make sense!
Another update - I just downloaded and ran FunHouse, one of the SDK sample applications that also uses NSOpenPanel. Well don't I feel special. It exhibits the same exact behavior. So from this I conclude either Apple has a bug in their code, my machine is special and messed up, and finally, it is Not my code that is at fault. That being the best part. Tomorrow, I will use a friends Mac and see if the same behavior is exhibited on his box.
This is just too weird.
I rebooted my box, took it to work and found it worked like a charm! I will assume this is fixed and has nothing to do with any other connected devices at home as compared to at work.
If it re-exhibits at home, then it is a network/device issue. Thanks all for your inputs and suggestions! Very much appreciated.
What, specifically, does the debugger say? It's possible that your program crashed, so the debugger is showing you information about the crash.
What if you omit any attempt to run an Open panel?