Xcode调试攻略(2)

           2.2 使用场景:

                   程序因为SIGABRT而crash，想要定位到导致crash的行。

3. 添加符号断点(Add Symbolic BreakPoint):

          3.1 断点执行的时机：Symbolic breakpoints stop program execution when a specific function or method starts executing

          3.2 添加步骤:

                  1. Steps In the bottom-left corner of the breakpoint navigator, click the Add button.

                  2. Choose Add Symbolic Breakpoint.
                  3. Enter the symbol name in the Symbol field.
                  4. Click Done.

          3.3 使用场景:

                       当想让系统在某个指定条件处中断时，设置相应的断点。

                       比如:

                              objc_exception_throw:在系统抛出异常处设置断点。

                              -[NSException raise]：

4. 设置NSZombieEnabled、MallocStackLogging、NSAutoreleaseFreedObjectCheckEnabled、NSDebugEnabled：

         4.1 设置方法:

                1. Product->Edit Scheme...->Run...->EnvironmentVariables.
                2. add NSZombieEnabled，set the value with YES
                3. add MallocStackLogging, set the value with YES.

                4. add NSAutoreleaseFreedObjectCheckEnabled, set the value with YES.

                5. add NSDebugEnabled, set the value with YES.