Yet Another Debug Output (NSLog Replacement)

Although NSlog is convenient for outputting messages to the console, I tire of the date/time and object information that it prints.

As an alternative, one can craft a macro that uses CFShow, which outputs Core Foundation objects to stderr. CFShow uses callbacks to objects to display their descriptions, which allows one to use “%@” like you would when calling NSLog.

I often include the following debug definition as part of my projects:

#define debug(format, ...) CFShow([NSString stringWithFormat:format, ## __VA_ARGS__]);

A few short examples follow showing the difference in output between NSLog and the debug macro shown above.

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struct point { int x; int y; }; typedef struct point POINT;   POINT topLeft; topLeft.x = 15, topLeft.y = 20;   NSLog(@"x: %d y: %d", topLeft.x, topLeft.y); debug(@"x: %d y: %d", topLeft.x, topLeft.y);

The output will now look as follows:

Here’s another example, this time passing in an object:

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NSDate *today = [NSDate date]; NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init]; [dateFormat setDateFormat:@"EEEE MMMM d, YYYY"]; NSString *dateString = [dateFormat stringFromDate:today]; [dateFormat release];   ...   NSLog(@"Date: %@", dateString); debug(@"Date: %@", dateString);

And the corresponding output:

Ahhh, much better.