Question

In my Function below if I remove the tempString release statement it works just fine but with it, there is ALWAYS a runtime error. It is a simple function that displays an array in an NSTextField either _stackDisp1 or _stackDisp2 but for some reason releasing the string creates a runtime error Any help?

- (void) displayArr:(NSMutableArray*)stack{
  NSTextField *myObj;
  if([stack count] <= 10) myObj = _stackDisp1;
  else myObj = _stackDisp2;
  NSString *tempString = [[NSString alloc]initWithString:@""];
  for(NSString *i in stack){
    tempString = [NSString stringWithFormat:@"%@\n%@",tempString,i];
  }
  [myObj setStringValue:tempString];
  [tempString release];
}

Answer 1

That’s because

tempString = [NSString stringWithFormat:@"%@\n%@",tempString,i];

creates a new autoreleased object assigning it to your variable tempString. The pointer to the first object gets lost and you end up over-releasing an autoreleased object. Just change the initial assignment to

  NSString *tempString = @"";

and remove the [tempString release] line.