NSUndoManager是否保留其参数？

Question

以下是由Aaron Hillegas为OS X的书籍可可编程启用撤销的代码：

-(void)removeObjectFromEmployeesAtIndex:(NSUInteger)index
{
Person *p = [employees objectAtIndex:index];
NSLog(@"removing %@ from %@", p, employees);
// Add the inverse of this operation to the undo stack 
NSUndoManager *undo = [self undoManager]; [[undo prepareWithInvocationTarget:self]  insertObject:p inEmployeesAtIndex:index]; 

if (![undo isUndoing]) { 
  [undo setActionName:@"Remove Person"];
} 
[employees removeObjectAtIndex:index];
}

在删除员工时，我们将命令推送到撤消堆栈以将该员工重新插入阵列。但是，当调用撤消时，有什么保证不会被释放？

Answer 1

当NSInvocation由“[[undo prepareWithInvocationTarget：self] insertObject：p inEmployeesAtIndex：index]”创建时，

'p'将被保留“