Variables reset after calling with IBAction

In Objective-c, I have variables set in the interface file:

#import <Cocoa/Cocoa.h>

@interface TestApp_BotAppDelegate : NSObject <NSApplicationDelegate> 
    {
   NSString * someString;
    }
- (IBAction) doSomething:(id)sender;

@end

And have this

#import "TestApp_BotAppDelegate.h"
@implementati开发者_运维知识库on TestApp_BotAppDelegate

@synthesize window;
@synthesize Buildings;
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
    {
    someString=@"HELLO";
    }

- (IBAction) doSomething:(id) sender
    {
    NSLog(@"%@", someString);
    }
@end

When i call doSomething from a button in the UI, I get a bad access error.

I know you that this is supposed to happen, but I don't know why or a workaround.

Thanks, Will

You are getting a bad access error because the string is not being properly managed in memory as explained in this question: EXC_BAD_ACCESS signal received. According the the code you posted you are never allocing and initializing someString, and therefore never releasing it. I believe you are not receiving null because the someString object never is taking up any memory to begin with.