宏

#if ! __has_feature(objc_arc)

#warning This file must be compiled with ARC. Use -fobjc-arc flag (or convert project to ARC).

#endif

判断该文件是否采用的是ARC,如果不是提示用户将该文件设置为ARC,或者把项目设为ARC

#if TARGET_OS_IPHONE

// Note: You may need to add the CFNetwork Framework to your project

#import <CFNetWork/CFNetWork.h>

#endif

判断如果目标运行在Iphone上,导入CFNetWork框架.

#ifndef MAC_OS_X_VERSION_MIN_REQUIRED

#ifdef __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__

#if (__i386__ || __x86_64__) && (__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < MAC_OS_X_VERSION_10_4)

#warning Building for Intel with Mac OS X Deployment Target < 10.4 is invalid.

#endif

#define MAC_OS_X_VERSION_MIN_REQUIRED __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__

#else

#if __i386__ || __x86_64__

#define MAC_OS_X_VERSION_MIN_REQUIRED MAC_OS_X_VERSION_10_4

#elif __arm__ || __arm64__

#define MAC_OS_X_VERSION_MIN_REQUIRED MAC_OS_X_VERSION_10_5

#else

#define MAC_OS_X_VERSION_MIN_REQUIRED MAC_OS_X_VERSION_10_1

#endif

#endif

#endif

````

//传入3位16进制的数,返回对应的UIColor实例

#define UIColorFromRGB(rgbValue) [UIColor colorWithRed:((float)((rgbValue & 0xFF0000) >> 16))/255.0 green:((float)((rgbValue & 0xFF00) >> 8))/255.0 blue:((float)(rgbValue & 0xFF))/255.0 alpha:1.0]

//self.view.backgroundColor = UIColorFromRGB(0XEEEEEE);

```python@requires_authorizationdef somefunc(param1='', param2=0):'''A docstring'''if param1 > param2: # interestingprint 'Greater'return (param2 - param1 + 1) or Noneclass SomeClass:pass>>> message = '''interpreter... prompt'''```