iOS:调试时在XCode中添加异常断点

调试iOS程序时，可以在XCode中添加异常断点，当出现objective C或者C++异常时，停留在抛出或捕获异常的代码处。

In XCode:

1. In the bottom-left corner of the breakpoints navigator, click the Add button;
2. Choose Add Exception Breakpoint;
3. Select Exception type and stage, using default should be fine.