問題1：Exception Type: 00000020 Exception Codes: 0x000000008badf00d Exception Note: SIMULATED (this is NOT a crash) Application Specific Information:com.wwc.test1 failed to scene-create after 19.94s (launch took 0.06s of total time limit 20.00s)
解答：app如果在20s內沒有啟動，系統的時間狗就會將程序殺死。也就會說應用啟動超時。（注意：程序在真機調試的時候超時，時間狗是不起作用的）
問題2：Exception Type: 00000020 Exception Codes: 0x000000008badf00d Exception Note: SIMULATED (this is NOT a crash) Highlighted by Thread: 11 Application Specific Information:
<BKNewProcess: 0x12f623190; com.sina.weibo; pid: 10924; hostpid: -1> has active assertions beyond permitted time:
{(
<BKProcessAssertion: 0x12f653f20> id: 10924-F212D20C-B907-46DA-88BB-23E9BF606091 name: Called by UIKit, from <redacted> process: <BKNewProcess: 0x12f623190; com.sina.weibo; pid: 10924; hostpid: -1> permittedBackgroundDuration: 180.000000 reason: finishTask owner pid:10924 preventSuspend preventIdleSleep preventSuspendOnSleep
)}
解答：The result is that when we go into the background, the watchdog process sees that the app is behaving badly and kills it summarily.（程序退出到后台后，在某一時刻被時間狗殺死）
問題3：Exception Type: EXC_RESOURCE Exception Subtype: WAKEUPS Exception Message: (Limit 150/sec) Observed 435/sec over 300 secs Exception Note: NON-FATAL CONDITION (this is NOT a crash)
解答：Background threads in iOS 8 have a hard limit on how many times you can run a sleep/wake cycle on each thread per second, and having a high count here is usually an indication that something is wrong / inefficient in your thread management.（后台線程的睡眠喚起次數是有限制的 150次）
問題4：EXC_BAD_ACCESS一般是內存管理引起的，且在控制台不會輸出錯誤信息（因為訪問的內部不確定從什么時候已被損壞），在手動管理內存的情況先可能經常見到；在ARC下出現的概率降低，但是有時也會出現。（訪問損壞的內存地址），有時候報錯EXC_BAD_ACCESS（SIGSEGV），SIGSEGV是當一個進程執行了一個無效的內存引用
解答：1.設置NSZombie（僵屍對象）調試程序 2.對程序做Analyze分析
問題5：SIGABRT 當異常終止一個進程。中止當前進程，返回一個錯誤代碼。該函數產生SIGABRT信號並發送給自己。實際就是系統發現操作異常，調用發送SIGABRT（abort()函數）信號，殺死進程。
解答：這種異常，系統會知道程序在什么地方有不合法的操作，會在控制台輸出異常信息。例如：向一個對象發送它無法識別的消息。
-(BOOL) respondsToSelector:(SEL)aSelector {
printf("SELECTOR: %s\n", [NSStringFromSelector(aSelector) UTF8String]);
return [super respondsToSelector:aSelector];
}