Is it ok to submit the iPhone app binary with NSLog statements ?

Question

Hello all ,

I am just about to submit my first iPhone app.

I have put lots of NSLog statements to test and debug the application .

So my question is " Is it ok to keep the NSLog statements in the source code "

and I have a doubt that whether the nslog statements slows down the total execution time or not .

thanks.

Answer 1

The three apps I have on the AppStore are loaded with NSLogs so I guess it's okay...

Answer 2

I've never got rid of mine :)

Some people recommend conditional compiling / compiler macros so you can make a build without any NSLog at all but I think that's too much effort for very little reward.

However, NSLogs do slow the app down (slightly) so I'd remove any ones that are directly affecting performance. Also, you might want to remove some debugging logging information to hide how you have implemented your app etc.

Hope that's helpful,

Sam

Answer 3

An app I was working on perviously had many NSLogs dumping debug to the console. We found that they hindered performance drastically on the iPhone 3G. The performance hit was noticeable on a 3GS, but not as much.

My advice would be to use a preprocessor macro and a debug preprocessor definition to conditionally use NSLogs in debug builds but not in release builds.

Answer 4

I used this all the time (found it somewhere):

// DLog is almost a drop-in replacement for NSLog to turn off logging for release build
// 
// add -DDEBUG to OTHER_CFLAGS in the build user defined settings
//
// Usage:
//
// DLog();
// DLog(@"here");
// DLog(@"value: %d", x);
// Unfortunately this doesn't work DLog(aStringVariable); you have to do this instead DLog(@"%@", aStringVariable);
//

#ifdef DEBUG
#   define DLog(__FORMAT__, ...) NSLog((@"%s [Line %d] " __FORMAT__), __PRETTY_FUNCTION__, __LINE__, ##__VA_ARGS__)
#else
#   define DLog(...) do {} while (0)
#endif
// ALog always displays output regardless of the DEBUG setting
#define ALog(__FORMAT__, ...) NSLog((@"%s [Line %d] " __FORMAT__), __PRETTY_FUNCTION__, __LINE__, ##__VA_ARGS__)

The three20 project from Facebook has more complex way to debug or logging.

Answer 5

I simply use a "useDebugMode" singleton int set to 0 or 1 that is stored in userPrefs (plist). And, depending on the UUID of the iphone, I add a "Use Debug Mode: on/off" toggle to the settings screen so i can debug problems in the future with production versions. This allows me to debug data problems (with downloaded XML) if people complain about issues with the program in the future. I then wrap all "NSLog"s and "printf"s in

if (useDebugLog == 1)
{
     NSLog(@"debug statement");
}

This works for me...Of course, the:

 if (useDebugLog == 1)

causes some overhead that I am willing to deal with.