如何追踪 Cocoa 应用程序中的分段错误？
我正在编写的 Cocoa 应用程序遇到问题。它必须解析每小时更新一次的带时间戳的文件，在测试过程中，由于分段错误，它在晚上 11:45 左右持续崩溃。我假设我必须向一个已被释放的对象发送消息。 Xcode 安装提供了哪些工具来跟踪对象分配并（希望）告诉我是否正在向已释放的对象发送消息？
我使用的是 Mac OS X 10.5。
I'm having a problem with a Cocoa application I am writing. It has to parse a timestamped file that is updated every hour, and during testing it keeps crashing consistently at around 11:45 PM due to a segmentation fault. I'm assuming I must be messaging an object that has been deallocated. What tools are provided with the Xcode install to track object allocations and (hopefully) tell me if I am messaging an object that has been deallocated?
I am using Mac OS X 10.5.
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我建议如下：
NSZombieEnabled来监视消息何时被发送到释放的 NSObjectsI would recommend the following:
NSZombieEnabledto monitor when messages are sent to deallocated NSObjects我的方法是使用名为
gdb的命令行工具。 这里是有关如何使用它的教程。您必须学习它的一些命令，但一旦您学会了，使用它几乎是一种乐趣。注意：
gbd可用于 C、C++ 和 Objective-C 程序。The way I do it is by using a command line tool called
gdb. Here is a tutorial on how to use it. You'll have to learn a few of it's commands, but once you do it's almost a pleasure to use.Note:
gbdcan be used on C, C++, and Objective-C programs.你在gdb下运行过程序吗？这应该允许您在 SIGSEGV 时检查堆栈和变量。
要跟踪分配情况，请使用 malloc_history。这需要设置
MallocStackLogging环境变量。Have you run the program under gdb? This should allow you to inspect the stack and variables when it SIGSEGVs.
To track allocations, use malloc_history. This requires the
MallocStackLoggingenvironment variable to be set.快速说明一下：使用已释放的内存位置通常会导致
EXC_BAD_ACCESS异常。如果这是您看到的崩溃原因，那么您认为这是释放问题是正确的。A quick point: using a deallocated memory location usually results in a
EXC_BAD_ACCESSexception. If that's the crash reason you're seeing then you're correct in assuming it's a deallocation problem.在 Xcode 的调试器（顶部有 GUI 的 gdb）中运行它并重现崩溃。然后，查看堆栈跟踪。
向已释放的对象发送消息通常在 objc_msgSend 中具有顶部框架。下一步是使用 NSZombieEnabled 运行应用程序并重现崩溃；僵尸会识别自己的身份。
Run it in Xcode's debugger (which is gdb with a GUI on top) and reproduce the crash. Then, look at the stack trace.
Messaging a deallocated object usually has the top frame in objc_msgSend. The next step then is to run the app with NSZombieEnabled and reproduce the crash; the zombie will identify itself.