Use of NSLog and NSLog

Use of NSLog and NSLog

1. NSLog prints strings in two places: the operating system console and the IDE console.

2. For NSLog, a printed destination is not the console, but the system file "system. log ".

Another output destination is not the IED console, but stderr.

 

Log description

-(NSString *) description This interface is owned by all NSObject and its subclass methods. By default, % @ In the NSLog parameter reads the return value of this method and prints it out, however, most subclasses do not specifically rewrite this method, resulting in the printed structure directly using the implementation content of the "description" interface in the parent NSObject class as the output, that is, the object pointer.