CMLog宏详解-优快云博客

CMLog: 用它来代替NSLog：

#define CMLog(format, ...) NSLog(@"%s:%@", __PRETTY_FUNCTION__,[NSString stringWithFormat:format, ## __VA_ARGS__]);

它的作用是将调用它的类和方法的名称一起输出到控制台。比如你在MyAppDelegate类的applicationDidFinishLaunching方法中调用它：

CMLog(@"My iPhone is an %@, v %@", [[UIDevice currentDevice] model], [[UIDevice currentDevice] systemVersion]);

控制台将输出：

2009-01-05 10:06:28.957 MyApp15173:20b]   
     -[MyAppDelegate applicationDidFinishLaunching:]:  
My iPhone is an iPhone Simulator, v 2.2

MARK: 此宏用于输出调用它的类和方法名称。适用于只想知道是否一个方法被调用了。

#define MARK    CMLog(@"%s", __PRETTY_FUNCTION__);

START_TIMER和END_TIMER: 用于确定一个方法或一段代码的运行时间：

 #define START_TIMER NSTimeInterval start = [NSDate timeIntervalSinceReferenceDate];    
#define END_TIMER(msg)  NSTimeInterval stop = [NSDate timeIntervalSinceReferenceDate];   
CMLog([NSString stringWithFormat:@"%@ Time = %f";, msg, stop-start]);

将START_TIMER 置于需评测的代码段开始处，并将END_TIMER置于代码段结束处，你就可获得这段代码的运行时间：

 - (NSData *)loadDataFromURL:(NSString *)dataURL    
{      
    START_TIMER;      
    NSData *data = [self doSomeStuff:dataURL];      
    END_TIMER(@"loadDataFromURL");      
    return data;    
}

输出为:

2009-01-05 10:31:37.943 MyApp[15283:20b] -[MyAppDelegate loadDataFromURL:]:  
loadDataFromURL Time = 3.636021

将所有这些宏定义整理使用条件标志放在预编译的头文件中。调试时，此标志设为1 ，发布时将其设为0 。

#if DEBUG==1    
   #define CMLog(format, ...) NSLog(@"%s:%@";, __PRETTY_FUNCTION__,[NSString stringWithFormat:format, ## __VA_ARGS__]);     
   #define MARK    CMLog(@"%s";, __PRETTY_FUNCTION__);    
   #define START_TIMER NSTimeInterval start = [NSDate timeIntervalSinceReferenceDate];    
   #define END_TIMER(msg)  NSTimeInterval stop = [NSDate timeIntervalSinceReferenceDate]; 
CMLog([NSString stringWithFormat:@"%@ Time = %f";, msg, stop-start]);    
else    
   #define CMLog(format, ...)    
   #define MARK  #define START_TIMER    
   #define END_TIMER(msg)    
endif