详细内容
添加方法：
Project -> Scheme -> Edit Scheme ，在 Arguments 下可以添加运行时的环境变量( Environment Variables )
变量名介绍备注
OBJC_PRINT_OPTIONS list which options are set 输出OBJC已设置的选项
OBJC_PRINT_IMAGES log image and library names as they are loaded输出已load的image信息
OBJC_PRINT_LOAD_METHODS log calls to class and category +load methods打印 Class 及 Category 的 + (void)load 方法的调用信息
OBJC_PRINT_INITIALIZE_METHODS log calls to class +initialize methods打印 Class 的 + (void)initialize 的调用信息
OBJC_PRINT_RESOLVED_METHODS log methods created by +resolveClassMethod and +resolveInstanceMethod:打印通过 +resolveClassMethod: 或 +resolveInstanceMethod: 生成的类方法
OBJC_PRINT_CLASS_SETUP log progress of class and category setup打印 Class 及 Category 的设置过程
OBJC_PRINT_PROTOCOL_SETUP log progress of protocol setup打印 Protocol 的设置过程
OBJC_PRINT_IVAR_SETUP log processing of non-fragile ivars打印 Ivar 的设置过程
OBJC_PRINT_VTABLE_SETUP log processing of class vtables打印 vtable 的设置过程
OBJC_PRINT_VTABLE_IMAGES print vtable images showing overridden methods打印 vtable 被覆盖的方法
OBJC_PRINT_CACHE_SETUP log processing of method caches打印方法缓存的设置过程
OBJC_PRINT_FUTURE_CLASSES log use of future classes for toll-free bridging打印从 CFType 无缝转换到 NSObject 将要使用的类（如 CFArrayRef 到 NSArray * ）
OBJC_PRINT_GClog some GC operations打印一些垃圾回收操作
OBJC_PRINT_PREOPTIMIZATION log preoptimization courtesy of dyld shared cache打印 dyld 共享缓存优化前的问候语
OBJC_PRINT_CXX_CTORS log calls to C++ ctors and dtors for instance variables打印类实例中的 C++ 对象的构造与析构调用
OBJC_PRINT_EXCEPTIONS log exception handling打印异常处理
OBJC_PRINT_EXCEPTION_THROW log backtrace of every objc_exception_throw()打印所有异常抛出时的 Backtrace
OBJC_PRINT_ALT_HANDLERS log processing of exception alt handlers打印 alt 操作异常处理
OBJC_PRINT_REPLACED_METHODS log methods replaced by category implementations打印被 Category 替换的方法
OBJC_PRINT_DEPRECATION_WARNINGS warn about calls to deprecated runtime functions打印所有过时的方法调用
OBJC_PRINT_POOL_HIGHWATER log high-water marks for autorelease pools打印 autoreleasepool 高水位警告
OBJC_PRINT_CUSTOM_RR log classes with un-optimized custom retain/release methods打印含有未优化的自定义 retain/release 方法的类
OBJC_PRINT_CUSTOM_AWZ log classes with un-optimized custom allocWithZone methods打印含有未优化的自定义 allocWithZone 方法的类
OBJC_PRINT_RAW_ISA log classes that require raw pointer isa fields打印需要访问原始 isa 指针的类
OBJC_DEBUG_UNLOAD warn about poorly-behaving bundles when unloaded卸载有不良行为的 Bundle 时打印警告
OBJC_DEBUG_FRAGILE_SUPERCLASSES warn about subclasses that may have been broken by subsequent changes to superclasses当子类可能被对父类的修改破坏时打印警告
OBJC_DEBUG_FINALIZERS warn about classes that implement -dealloc but not -finalize警告实现了 -dealloc 却没有实现 -finalize 的类
OBJC_DEBUG_NIL_SYNC warn about @synchronized(nil), which does no synchronization警告 @synchronized(nil) 调用，这种情况不会加锁
OBJC_DEBUG_NONFRAGILE_IVARS capriciously rearrange non-fragile ivars打印突发地重新布置 non-fragile ivars 的行为
OBJC_DEBUG_ALT_HANDLERS record more info about bad alt handler use记录更多的 alt 操作错误信息
OBJC_DEBUG_MISSING_POOLS warn about autorelease with no pool in place, which may be a leak警告没有 pool 的情况下使用 autorelease，可能内存泄漏
OBJC_DEBUG_DUPLICATE_CLASSES halt when multiple classes with the same name are present当出现类重名时停机
OBJC_USE_INTERNAL_ZONE allocate runtime data in a dedicated malloc zone在一个专用的 malloc 区分配运行时数据
OBJC_DISABLE_GC force GC OFF, even if the executable wants it on强行关闭自动垃圾回收，即使可执行文件需要垃圾回收
OBJC_DISABLE_VTABLES disable vtable dispatch关闭 vtable 分发
OBJC_DISABLE_PREOPTIMIZATION disable preoptimization courtesy of dyld shared cache关闭 dyld 共享缓存优化前的问候语
OBJC_DISABLE_TAGGED_POINTERS disable tagged pointer optimization of NSNumber et al.关闭 NSNumber 等的 tagged pointer 优化
OBJC_DISABLE_NONPOINTER_ISA disable non-pointer isa fields关闭 non-pointer isa 字段的访问
